NEWS

# [4.18.0](https://github.com/ezyang/htmlpurifier/compare/v4.17.0...v4.18.0) (2024-11-01)


### Bug Fixes

* Adjust Core.AllowHostnameUnderscore to consider that "_" is defined as Unreserved Characters in RFC 3986 ([#406](https://github.com/ezyang/htmlpurifier/issues/406)) ([d9fbef8](https://github.com/ezyang/htmlpurifier/commit/d9fbef8e27f6a0848a8987a8534351de98eb0fa1))
* Avoid a deprecated error when the attribute name is numeric and DirectLex is used ([#412](https://github.com/ezyang/htmlpurifier/issues/412)) ([f0fbf51](https://github.com/ezyang/htmlpurifier/commit/f0fbf510981b27fc03168efdb17d6bff48f521af))
* checking that node has property name ([#399](https://github.com/ezyang/htmlpurifier/issues/399)) ([9ca5a36](https://github.com/ezyang/htmlpurifier/commit/9ca5a3687bd2e6e42ed9d5199b2cfb1dbd6dbdc2))
* Ignore conditional comments ([#401](https://github.com/ezyang/htmlpurifier/issues/401)) ([4828fdf](https://github.com/ezyang/htmlpurifier/commit/4828fdf45a93eeeacfcbcc855f96f9a7e6b4ed44))
* Support PHP 8.4 ([#396](https://github.com/ezyang/htmlpurifier/issues/396)) ([92da247](https://github.com/ezyang/htmlpurifier/commit/92da2473ffbb3ed5e894560d4166b1ca8032aeb3))
* undefined array key warning ([#419](https://github.com/ezyang/htmlpurifier/issues/419)) ([01be377](https://github.com/ezyang/htmlpurifier/commit/01be377f93654fad4d3fbc8c81779f14316eaecf))


### Features

* Add allowfullscreen attr for iframe ([#411](https://github.com/ezyang/htmlpurifier/issues/411)) ([70754a2](https://github.com/ezyang/htmlpurifier/commit/70754a253342f67a67425cfa81029db3a5c1bd28))
* add directive for removing blank nodes ([#404](https://github.com/ezyang/htmlpurifier/issues/404)) ([c9d60c9](https://github.com/ezyang/htmlpurifier/commit/c9d60c96d799c02bc357c88a49f422034b6914fd))
* Add support for CSS aspect-ratio ([#408](https://github.com/ezyang/htmlpurifier/issues/408)) ([93bee73](https://github.com/ezyang/htmlpurifier/commit/93bee733497a098b65daf5910f1c435d347860a4))
* Allow universal CSS values for all properties ([#410](https://github.com/ezyang/htmlpurifier/issues/410)) ([9723267](https://github.com/ezyang/htmlpurifier/commit/972326785d201b81e1095bc296b99bbcfa8c7fd4))

# [4.17.0](https://github.com/ezyang/htmlpurifier/compare/v4.16.0...v4.17.0) (2023-11-17)


### Bug Fixes

* CSSTidy ImportantComments not handled properly ([#359](https://github.com/ezyang/htmlpurifier/issues/359)) ([78a9b4d](https://github.com/ezyang/htmlpurifier/commit/78a9b4d0dae8bce9a70e4e7e551bf51e9a23706d))
* fix CI ([#361](https://github.com/ezyang/htmlpurifier/issues/361)) ([9ec687c](https://github.com/ezyang/htmlpurifier/commit/9ec687c904a1fe66a5395d22c50f7043e045d1d3))
* Invalid scheme check in Attr.TargetBlank ([#363](https://github.com/ezyang/htmlpurifier/issues/363)) ([0176ef4](https://github.com/ezyang/htmlpurifier/commit/0176ef4bb6f57103fdcb60a802603e60e81ee93e))
* semantic release ([#339](https://github.com/ezyang/htmlpurifier/issues/339)) ([d82f3d9](https://github.com/ezyang/htmlpurifier/commit/d82f3d996a0d9b0f23364946d9a14408c1ad72c5))
* semantic release ([#341](https://github.com/ezyang/htmlpurifier/issues/341)) ([e55fead](https://github.com/ezyang/htmlpurifier/commit/e55fead09f39430d30f48438f06e7bc2326efc94)), closes [#339](https://github.com/ezyang/htmlpurifier/issues/339)
* Support for locales using decimal separators other than . (dot) ([#372](https://github.com/ezyang/htmlpurifier/issues/372)) ([43f49ac](https://github.com/ezyang/htmlpurifier/commit/43f49ac9a51b81dfd07d3bc8dcfc5ec5637a5e3b))


### Features

* Add support for all text-decoration properties ([#360](https://github.com/ezyang/htmlpurifier/issues/360)) ([2d775c0](https://github.com/ezyang/htmlpurifier/commit/2d775c01874e2f676ba1a2d9fe69b47c2a823061))
* Allows commas to be included in tel URI ([#389](https://github.com/ezyang/htmlpurifier/issues/389)) ([ec92490](https://github.com/ezyang/htmlpurifier/commit/ec924901392f088d334622f806b9449b17b75d7b)), closes [#388](https://github.com/ezyang/htmlpurifier/issues/388)


### Reverts

* Revert "fix: semantic release (#339)" (#340) ([3e83215](https://github.com/ezyang/htmlpurifier/commit/3e832152a6173f880c6495a3ab2b0e5235e253a6)), closes [#339](https://github.com/ezyang/htmlpurifier/issues/339) [#340](https://github.com/ezyang/htmlpurifier/issues/340)

NEWS ( CHANGELOG and HISTORY )                                     HTMLPurifier
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= KEY ====================
    # Breaks back-compat
    ! Feature
    - Bugfix
      + Sub-comment
    . Internal change
==========================

4.15.0, released 2022-09-18
! PHP 8.1 and 8.2 support, esp. fixes for deprecation warnings.  A joint effort
  by David Rans, Tim Düsterhus, Kieran and John Flatness.
! Allow contenteditable="false" (#336), contributed by Kieran.
- Replace PHP 8.1 deprecated utf8_ functions with mbstring (#326),
  contributed by John Flatness.
- Enhanced composer suggestions with extensions (#317), contributed by
  func0der.

4.14.0, released 2021-12-24
! Add "background-size" support (#289), contributed by Václav Smítal
! Transform deprecated width attribute when tidying HTML, contributed by
  Kieran.
- PHP 8 support, contributed by Maksims Sļotovs.
- Improved PHP 7.3 compatibility, contributed by kishor.
- Avoid spurious magic quotes notice in PHP 7.4.  Thanks
  Jasper Zonneveld for the fix.
- Do not remove thead from table even if there are no tbody/tr (#264).
  Thanks Marcus Artner for the fix.
- Fix "Parameter must be an array or an object that implements
  Countable" (#285)".  Thanks Kieran for this fix.
. Fix unnecessary reference assignment, handling behavior change from
  PHP5 and PHP7.  Thanks Arkadiusz Biczewski for the fix.

4.13.0, released 2020-06-28
! Add %HTML.Forms directive, which lets you accept forms in user
  HTML without requiring full %HTML.Trusted.  Note that forms can
  be (trivially) used to setup phishing; e.g., an attacker can
  use CSS absolute positioning to overlay a form on top of a login
  element, so please be sure to use this with care!   Fixes #213.
  Thanks Mateusz Turcza for contributing this feature.
! tr@bgcolor attribute is now supported.  Thanks Kieran Brahney
  for this enhancement.
- Further improvements to PHP 7.4 support, contributed by Witold
  Wasiczko and Eloy Lafuente.
- Fix PSR-0 compatibility.  Thanks Jordi Boggiano for contributing
  part of this fix.
- Fix bug with purifyArray where it doesn't work on empty arrays.
  Thanks Fräntz Miccoli for the fix.
- Reduce amount of maintenance scripts included in distribution
  packages.  Thanks Sergei Morozov for this patch.
- Remove leading zeros unless if it is only a zero, fixes #239.  Thanks
  lubomirbartos for this fix.
- Correct type hinting of maybeGet*, fixes #240.   Thanks Anders Jenbo
  for this fix.

4.12.0, released 2019-10-27
! PHP 7.4 is supported, thank you Witold Wasiczko, Mateuz Turcza and
  Edi Modrić
- PHPDocs for HTMLModule::addElement() and Bool attr are fixed (thanks
  Mateusz)

4.11.0, released 2019-07-14
# SafeScripting now matches case-sensitively against its whitelist (previously it was
  case-insensitive.)  Thanks Dimitri Gritsajuk <gritsajuk.dimitri@gmail.com>
  for reporting.
! New directive %Core.AllowParseManyTags which allows parsing of many nested tags.
  Thanks M. Suzuki <msuzuki1986@gmail.com> for contributing the patch.
! purifyArray now supports multidimensional arrays.  Thanks
  Sandro Miguel Marques <sandromiguel@sandromiguel.com> for contributing this patch.
! initial and inherit settings available for width, height, and the min-/max-
  versions thereof.  Thanks Michael Kliewe <info@phpgansta.de> for contributing
  this patch.
! More color names are supported.  Thanks Daijobou for contributing.
- Compatibility fixes for PHP 7.3, including new CI for PHP 7.3
  (thank you Lukas Neumann <lksnmnn@gmail.com>) and removal of
  reserved words in our constants (thanks Darko Hrgovic <darko@darkodev.com>
- Compatibility fixes for HHVM.  Thanks Mateusz Turcza for contributing
  this fix.
- HTML Purifier now never defines __autoload, fixing #196.  Thanks
  Michael Kliewe for reporting.
- In some situations, Config.php would report an undefined index: class
  error; this has been fixed.  Thanks DiLong Fa for contributing
  this fix.
- We no longer produce <script /> tags; we always explicitly write
  out the open and close tag.  Thanks Dimitri Gritsajuk
  <gritsajuk.dimitri@gmail.com> for contributing this fix.
- Better compatibility when IDNA constants are not present.  Thanks
  Mateusz Turcza <xemlock@gmail.com> for contributing this fix.

4.10.0, released 2018-02-22
# PHP 5.3 is no longer officially supported by HTML Purifier
  (we did not specifically break support, but we are no longer
  testing on PHP 5.3)
! Relative CSS length units are now supported
- A few PHP 7.2 compatibility fixes, thanks John Flatness
  <john@zerocrates.org>
- Improve portability with old versions of libxml which don't
  support accessing the data of a node
- IDNA2008 is now used for converting domains to ASCII, fixing
  some rather strange bugs with international domains
- Fix race condition resulting in E_WARNING when creating
  directories with Serializer

4.9.3, released 2017-06-02
- Workaround PHP 7.1 infinite loop when opcode cache is enabled.
  Thanks @Xiphin (#134, #135)
- Don't use autoloader when testing for DOMDocument.  Hypothetically,
  this could cause your install to start using DirectLex if you had
  previously been monkeypatching in a custom, autoloaded implementation
  of DOMDocument.  Don't do that.  Thanks @Izumi-kun (#130)

4.9.2, released 2017-03-12
- Fixes PHP 5.3 compatibility
- Fix breakage when decoding decimal entities.  Thanks @rybakit (#129)

4.9.1, released 2017-03-08
! %URI.DefaultScheme can now be set to null, in which case
  all relative paths are removed.
! New CSS properties: min-width, max-width, min-height, max-height (#94)
! Transparency (rgba) and hsl/hsla supported where color CSS is present.
  Thanks @fxbt for contributing the patch. (#118)
- When idn_to_ascii is defined, we might accept malformed
  hostnames.  Apply validation to the result in such cases.
- Close directory when done in Serializer DefinitionCache (#100)
- Deleted some asserts to avoid linters from choking (#97)
- Rework Serializer cache behavior to avoid chmod'ing if possible (#32)
- Embedded semicolons in strings in CSS are now handled correctly!
- We accidentally dropped certain Unicode characters if there was
  one or more invalid characters.  This has been fixed, thanks
  to mpyw <ryosuke_i_628@yahoo.co.jp>
- Fix for "Don't truncate upon encountering </div> when using DOMLex"
  caused a regression with HTML 4.01 Strict parsing with libxml 2.9.1
  (and maybe later versions, but known OK with libxml 2.9.4).  The
  fix is to go about handling truncation a bit more cleverly so that
  we can wrap with divs (sidestepping the bug) but slurping out the
  rest of the text in case it ran off the end.  (#78)
- Fix PREG_BACKTRACK_LIMIT_ERROR in HTMLPurifier_Filter_ExtractStyle.
  Thanks @breathbath for contributing the report and fix (#120)
- Fix entity decoding algorithm to be more conservative about
  decoding entities that are missing trailing semicolon.
  To get old behavior, set %Core.LegacyEntityDecoder to true.
  (#119)
- Workaround libxml bug when HTML tags are embedded inside
  script tags.  To disable workaround set %Core.AggressivelyRemoveScript
  to false. (#83)
# By default, when a link has a target attribute associated
  with it, we now also add rel="noopener" in order to
  prevent the new window from being able to overwrite
  the original frame.  To disable this protection,
  set %HTML.TargetNoopener to FALSE.

4.9.0 was cut on Git but never properly released; when we did the
real release we decided to skip this version number.

4.8.0, released 2016-07-16
# By default, when a link has a target attribute associated
  with it, we now also add rel="noreferrer" in order to
  prevent the new window from being able to overwrite
  the original frame.  To disable this protection,
  set %HTML.TargetNoreferrer to FALSE.
! Full PHP 7 compatibility, the test suite is ALL GO.
! %CSS.AllowDuplicates permits duplicate CSS properties.
! Support for 'tel' URIs.
! Partial support for 'border-radius' properties when %CSS.AllowProprietary is true.
  The slash syntax, i.e., 'border-radius: 2em 1em 4em / 0.5em 3em' is not
  yet supported.
! %Attr.ID.HTML5 turns on HTML5-style ID handling.
- alt truncation could result in malformed UTF-8 sequence. Don't
  truncate.  Thanks Brandon Farber for reporting.
- Linkify regex is smarter, based off of Gruber's regex.
- IDNA supported natively on PHP 5.3 and later.
- Non all-numeric top-level names (e.g., foo.1f, 1f) are now
  allowed.
- Minor bounds error fix to squash a PHP 7 notice.
- Support non-/tmp temporary directories for data:// validation
- Give a better error message when a user attempts to allow
  ul/ol without allowing li.
- On some versions of PHP, the Serializer DefinitionCache could
  infinite loop when the directory exists but is not listable. (#49)
- Don't match for <body> inside comments with
  %Core.ConvertDocumentToFragment. (#67)
- SafeObject is now less case sensitive. (#57)
- AutoFormat.RemoveEmpty.Predicate now correctly renders in
  web form. (#85)

4.7.0, released 2015-08-04
# opacity is now considered a "tricky" CSS property rather than a
  proprietary one.
! %AutoFormat.RemoveEmpty.Predicate for specifying exactly when
  an element should be considered "empty" (maybe preserve if it
  has attributes), and modify iframe support so that the iframe
  is removed if it is missing a src attribute.  Thanks meeva for
  reporting.
- Don't truncate upon encountering </div> when using DOMLex.  Thanks
  Myrto Christina for finally convincing me to fix this.
- Update YouTube filter for new code.
- Fix parsing of rgb() values with spaces in them for 'border'
  attribute.
- Don't remove foo="" attributes if foo is a boolean attribute.  Thanks
  valME for reporting.

4.6.0, released 2013-11-30
# Secure URI munge hashing algorithm has changed to hash_hmac("sha256", $url, $secret).
  Please update any verification scripts you may have.
# URI parsing algorithm was made more strict, so only prefixes which
  looks like schemes will actually be schemes.  Thanks
  Michael Gusev <mgusev@sugarcrm.com> for fixing.
# %Core.EscapeInvalidChildren is no longer supported, and no longer does
  anything.
! New directive %Core.AllowHostnameUnderscore which allows underscores
  in hostnames.
- Eliminate quadratic behavior in DOMLex by using a proper queue.
  Thanks Ole Laursen for noticing this.
- Rewritten MakeWellFormed/FixNesting implementation eliminates quadratic
  behavior in the rest of the purificaiton pipeline.  Thanks Chedburn
  Networks for sponsoring this work.
- Made Linkify URL parser a bit less permissive, so that non-breaking
  spaces and commas are not included as part of URL.  Thanks nAS for fixing.
- Fix some bad interactions with %HTML.Allowed and injectors.  Thanks
  David Hirtz for reporting.
- Fix infinite loop in DirectLex. Thanks Ashar Javed (@soaj1664ashar)
  for reporting.

4.5.0, released 2013-02-17
# Fix bug where stacked attribute transforms clobber each other;
  this also means it's no longer possible to override attribute
  transforms in later modules.  No internal code was using this
  but this may break some clients.
# We now use SHA-1 to identify cached definitions, instead of MD5.
! Support display:inline-block
! Support for more white-space CSS values.
! Permit underscores in font families
! Support for page-break-* CSS3 properties when proprietary properties
  are enabled.
! New directive %Core.DisableExcludes; can be set to 'true' to turn off
  SGML excludes checking.  If HTML Purifier is removing too much text
  and you don't care about full standards compliance, try setting this to
  'true'.
- Use prepend for SPL autoloading on PHP 5.3 and later.
- Fix bug with nofollow transform when pre-existing rel exists.
- Fix bug where background:url() always gets lower-cased
  (but not background-image:url())
- Fix bug with non lower-case color names in HTML
- Fix bug where data URI validation doesn't remove temporary files.
  Thanks Javier Marín Ros <javiermarinros@gmail.com> for reporting.
- Don't remove certain empty tags on RemoveEmpty.

4.4.0, released 2012-01-18
# Removed PEARSax3 handler.
# URI.Munge now munges URIs inside the same host that go from https
  to http.  Reported by Neike Taika-Tessaro.
# Core.EscapeNonASCIICharacters now always transforms entities to
  entities, even if target encoding is UTF-8.
# Tighten up selector validation in ExtractStyleBlocks.
  Non-syntactically valid selectors are now rejected, along with
  some of the more obscure ones such as attribute selectors, the
  :lang pseudoselector, and anything not in CSS2.1.  Furthermore,
  ID and class selectors now work properly with the relevant
  configuration attributes.  Also, mute errors when parsing CSS
  with CSS Tidy.  Reported by Mario Heiderich and Norman Hippert.
! Added support for 'scope' attribute on tables.
! Added %HTML.TargetBlank, which adds target="blank" to all outgoing links.
! Properly handle sub-lists directly nested inside of lists in
  a standards compliant way, by moving them into the preceding <li>
! Added %HTML.AllowedComments and %HTML.AllowedCommentsRegexp for
  limited allowed comments in untrusted situations.
! Implement iframes, and allow them to be used in untrusted mode with
  %HTML.SafeIframe and %URI.SafeIframeRegexp.  Thanks Bradley M. Froehle
  <brad.froehle@gmail.com> for submitting an initial version of the patch.
! The Forms module now works properly for transitional doctypes.
! Added support for internationalized domain names. You need the PEAR
  Net_IDNA2 module to be in your path; if it is installed, ensure the
  class can be loaded and then set %Core.EnableIDNA to true.
- Color keywords are now case insensitive.  Thanks Yzmir Ramirez
  <yramirez-htmlpurifier@adicio.com> for reporting.
- Explicitly initialize anonModule variable to null.
- Do not duplicate nofollow if already present.  Thanks 178
  for reporting.
- Do not add nofollow if hostname matches our current host.  Thanks 178
  for reporting, and Neike Taika-Tessaro for helping diagnose.
- Do not unset parser variable; this fixes intermittent serialization
  problems.  Thanks Neike Taika-Tessaro for reporting, bill
  <10010tiger@gmail.com> for diagnosing.
- Fix iconv truncation bug, where non-UTF-8 target encodings see
  output truncated after around 8000 characters.  Thanks Jörg Ludwig
  <joerg.ludwig@iserv.eu> for reporting.
- Fix broken table content model for XHTML1.1 (and also earlier
  versions, although the W3C validator doesn't catch those violations).
  Thanks GlitchMr <glitch.mr@gmail.com> for reporting.

4.3.0, released 2011-03-27
# Fixed broken caching of customized raw definitions, but requires an
  API change.  The old API still works but will emit a warning,
  see http://htmlpurifier.org/docs/enduser-customize.html#optimized
  for how to upgrade your code.
# Protect against Internet Explorer innerHTML behavior by specially
  treating attributes with backticks but no angled brackets, quotes or
  spaces.  This constitutes a slight semantic change, which can be
  reverted using %Output.FixInnerHTML.  Reported by Neike Taika-Tessaro
  and Mario Heiderich.
# Protect against cssText/innerHTML by restricting allowed characters
  used in fonts further than mandated by the specification and encoding
  some extra special characters in URLs.  Reported by Neike
  Taika-Tessaro and Mario Heiderich.
! Added %HTML.Nofollow to add rel="nofollow" to external links.
! More types of SPL autoloaders allowed on later versions of PHP.
! Implementations for position, top, left, right, bottom, z-index
  when %CSS.Trusted is on.
! Add %Cache.SerializerPermissions option for custom serializer
  directory/file permissions
! Fix longstanding bug in Flash support for non-IE browsers, and
  allow more wmode attributes.
! Add %CSS.AllowedFonts to restrict permissible font names.
- Switch to an iterative traversal of the DOM, which prevents us
  from running out of stack space for deeply nested documents.
  Thanks Maxim Krizhanovsky for contributing a patch.
- Make removal of conditional IE comments ungreedy; thanks Bernd
  for reporting.
- Escape CDATA before removing Internet Explorer comments.
- Fix removal of id attributes under certain conditions by ensuring
  armor attributes are preserved when recreating tags.
- Check if schema.ser was corrupted.
- Check if zend.ze1_compatibility_mode is on, and error out if it is.
  This safety check is only done for HTMLPurifier.auto.php; if you
  are using standalone or the specialized includes files, you're
  expected to know what you're doing.
- Stop repeatedly writing the cache file after I'm done customizing a
  raw definition.  Reported by ajh.
- Switch to using require_once in the Bootstrap to work around bad
  interaction with Zend Debugger and APC.  Reported by Antonio Parraga.
- Fix URI handling when hostname is missing but scheme is present.
  Reported by Neike Taika-Tessaro.
- Fix missing numeric entities on DirectLex; thanks Neike Taika-Tessaro
  for reporting.
- Fix harmless notice from indexing into empty string.  Thanks Matthijs
  Kooijman <matthijs@stdin.nl> for reporting.
- Don't autoclose no parent elements are able to support the element
  that triggered the autoclose.  In particular fixes strange behavior
  of stray <li> tags.  Thanks pkuliga@gmail.com for reporting and
  Neike Taika-Tessaro <pinkgothic@gmail.com> for debugging assistance.

4.2.0, released 2010-09-15
! Added %Core.RemoveProcessingInstructions, which lets you remove
  <? ... ?> statements.
! Added %URI.DisableResources functionality; the directive originally
  did nothing.  Thanks David Rothstein for reporting.
! Add documentation about configuration directive types.
! Add %CSS.ForbiddenProperties configuration directive.
! Add %HTML.FlashAllowFullScreen to permit embedded Flash objects
  to utilize full-screen mode.
! Add optional support for the <code>file</code> URI scheme, enable
  by explicitly setting %URI.AllowedSchemes.
! Add %Core.NormalizeNewlines options to allow turning off newline
  normalization.
- Fix improper handling of Internet Explorer conditional comments
  by parser.  Thanks zmonteca for reporting.
- Fix missing attributes bug when running on Mac Snow Leopard and APC.
  Thanks sidepodcast for the fix.
- Warn if an element is allowed, but an attribute it requires is
  not allowed.

4.1.1, released 2010-05-31
- Fix undefined index warnings in maintenance scripts.
- Fix bug in DirectLex for parsing elements with a single attribute
  with entities.
- Rewrite CSS output logic for font-family and url().  Thanks Mario
  Heiderich <mario.heiderich@googlemail.com> for reporting and Takeshi
  Terada <t-terada@violet.plala.or.jp> for suggesting the fix.
- Emit an error for CollectErrors if a body is extracted
- Fix bug where in background-position for center keyword handling.
- Fix infinite loop when a wrapper element is inserted in a context
  where it's not allowed.  Thanks Lars <lars@renoz.dk> for reporting.
- Remove +x bit and shebang from index.php; only supported mode is to
  explicitly call it with php.
- Make test script less chatty when log_errors is on.

4.1.0, released 2010-04-26
! Support proprietary height attribute on table element
! Support YouTube slideshows that contain /cp/ in their URL.
! Support for data: URI scheme; not enabled by default, add it using
  %URI.AllowedSchemes
! Support flashvars when using %HTML.SafeObject and %HTML.SafeEmbed.
! Support for Internet Explorer compatibility with %HTML.SafeObject
  using %Output.FlashCompat.
! Handle <ol><ol> properly, by inserting the necessary <li> tag.
- Always quote the insides of url(...) in CSS.

4.0.0, released 2009-07-07
# APIs for ConfigSchema subsystem have substantially changed. See
  docs/dev-config-bcbreaks.txt for details; in essence, anything that
  had both namespace and directive now have a single unified key.
# Some configuration directives were renamed, specifically:
    %AutoFormatParam.PurifierLinkifyDocURL -> %AutoFormat.PurifierLinkify.DocURL
    %FilterParam.ExtractStyleBlocksEscaping -> %Filter.ExtractStyleBlocks.Escaping
    %FilterParam.ExtractStyleBlocksScope -> %Filter.ExtractStyleBlocks.Scope
    %FilterParam.ExtractStyleBlocksTidyImpl -> %Filter.ExtractStyleBlocks.TidyImpl
  As usual, the old directive names will still work, but will throw E_NOTICE
  errors.
# The allowed values for class have been relaxed to allow all of CDATA for
  doctypes that are not XHTML 1.1 or XHTML 2.0.  For old behavior, set
  %Attr.ClassUseCDATA to false.
# Instead of appending the content model to an old content model, a blank
  element will replace the old content model.  You can use #SUPER to get
  the old content model.
! More robust support for name="" and id=""
! HTMLPurifier_Config::inherit($config) allows you to inherit one
  configuration, and have changes to that configuration be propagated
  to all of its children.
! Implement %HTML.Attr.Name.UseCDATA, which relaxes validation rules on
  the name attribute when set. Use with care. Thanks Ian Cook for
  sponsoring.
! Implement %AutoFormat.RemoveEmpty.RemoveNbsp, which removes empty
  tags that contain non-breaking spaces as well other whitespace. You
  can also modify which tags should have &nbsp; maintained with
  %AutoFormat.RemoveEmpty.RemoveNbsp.Exceptions.
! Implement %Attr.AllowedClasses, which allows administrators to restrict
  classes users can use to a specified finite set of classes, and
  %Attr.ForbiddenClasses, which is the logical inverse.
! You can now maintain your own configuration schema directories by
  creating a config-schema.php file or passing an extra argument. Check
  docs/dev-config-schema.html for more details.
! Added HTMLPurifier_Config->serialize() method, which lets you save away
  your configuration in a compact serial file, which you can unserialize
  and use directly without having to go through the overhead of setup.
- Fix bug where URIDefinition would not get cleared if it's directives got
  changed.
- Fix fatal error in HTMLPurifier_Encoder on certain platforms (probably NetBSD 5.0)
- Fix bug in Linkify autoformatter involving <a><span>http://foo</span></a>
- Make %URI.Munge not apply to links that have the same host as your host.
- Prevent stray </body> tag from truncating output, if a second </body>
  is present.
. Created script maintenance/rename-config.php for renaming a configuration
  directive while maintaining its alias.  This script does not change source code.
. Implement namespace locking for definition construction, to prevent
  bugs where a directive is used for definition construction but is not
  used to construct the cache hash.

3.3.0, released 2009-02-16
! Implement CSS property 'overflow' when %CSS.AllowTricky is true.
! Implement generic property list classes
- Fix bug with testEncodingSupportsASCII() algorithm when iconv() implementation
  does not do the "right thing" with characters not supported in the output
  set.
- Spellcheck UTF-8: The Secret To Character Encoding
- Fix improper removal of the contents of elements with only whitespace. Thanks
  Eric Wald for reporting.
- Fix broken test suite in versions of PHP without spl_autoload_register()
- Fix degenerate case with YouTube filter involving double hyphens.
  Thanks Pierre Attar for reporting.
- Fix YouTube rendering problem on certain versions of Firefox.
- Fix CSSDefinition Printer problems with decorators
- Add text parameter to unit tests, forces text output
. Add verbose mode to command line test runner, use (--verbose)
. Turn on unit tests for UnitConverter
. Fix missing version number in configuration %Attr.DefaultImageAlt (added 3.2.0)
. Fix newline errors that caused spurious failures when CRLF HTML Purifier was
  tested on Linux.
. Removed trailing whitespace from all text files, see
  remote-trailing-whitespace.php maintenance script.
. Convert configuration to use property list backend.

3.2.0, released 2008-10-31
# Using %Core.CollectErrors forces line number/column tracking on, whereas
  previously you could theoretically turn it off.
# HTMLPurifier_Injector->notifyEnd() is formally deprecated. Please
  use handleEnd() instead.
! %Output.AttrSort for when you need your attributes in alphabetical order to
  deal with a bug in FCKEditor. Requested by frank farmer.
! Enable HTML comments when %HTML.Trusted is on. Requested by Waldo Jaquith.
! Proper support for name attribute. It is now allowed and equivalent to the id
  attribute in a and img tags, and is only converted to id when %HTML.TidyLevel
  is heavy (for all doctypes).
! %AutoFormat.RemoveEmpty to remove some empty tags from documents. Please don't
  use on hand-written HTML.
! Add error-cases for unsupported elements in MakeWellFormed. This enables
  the strategy to be used, standalone, on untrusted input.
! %Core.AggressivelyFixLt is on by default. This causes more sensible
  processing of left angled brackets in smileys and other whatnot.
! Test scripts now have a 'type' parameter, which lets you say 'htmlpurifier',
  'phpt', 'vtest', etc. in order to only execute those tests. This supersedes
  the --only-phpt parameter, although for backwards-compatibility the flag
  will still work.
! AutoParagraph auto-formatter will now preserve double-newlines upon output.
  Users who are not performing inbound filtering, this may seem a little
  useless, but as a bonus, the test suite and handling of edge cases is also
  improved.
! Experimental implementation of forms for %HTML.Trusted
! Track column numbers when maintain line numbers is on
! Proprietary 'background' attribute on table-related elements converted into
  corresponding CSS.  Thanks Fusemail for sponsoring this feature!
! Add forward(), forwardUntilEndToken(), backward() and current() to Injector
  supertype.
! HTMLPurifier_Injector->handleEnd() permits modification to end tokens. The
  time of operation varies slightly from notifyEnd() as *all* end tokens are
  processed by the injector before they are subject to the well-formedness rules.
! %Attr.DefaultImageAlt allows overriding default behavior of setting alt to
  basename of image when not present.
! %AutoFormat.DisplayLinkURI neuters <a> tags into plain text URLs.
- Fix two bugs in %URI.MakeAbsolute; one involving empty paths in base URLs,
  the other involving an undefined $is_folder error.
- Throw error when %Core.Encoding is set to a spurious value. Previously,
  this errored silently and returned false.
- Redirected stderr to stdout for flush error output.
- %URI.DisableExternal will now use the host in %URI.Base if %URI.Host is not
  available.
- Do not re-munge URL if the output URL has the same host as the input URL.
  Requested by Chris.
- Fix error in documentation regarding %Filter.ExtractStyleBlocks
- Prevent <![CDATA[<body></body>]]> from triggering %Core.ConvertDocumentToFragment
- Fix bug with inline elements in blockquotes conflicting with strict doctype
- Detect if HTML support is disabled for DOM by checking for loadHTML() method.
- Fix bug where dots and double-dots in absolute URLs without hostname were
  not collapsed by URIFilter_MakeAbsolute.
- Fix bug with anonymous modules operating on SafeEmbed or SafeObject elements
  by reordering their addition.
- Will now throw exception on many error conditions during lexer creation; also
  throw an exception when MaintainLineNumbers is true, but a non-tracksLineNumbers
  is being used.
- Detect if domxml extension is loaded, and use DirectLEx accordingly.
- Improve handling of big numbers with floating point arithmetic in UnitConverter.
  Reported by David Morton.
. Strategy_MakeWellFormed now operates in-place, saving memory and allowing
  for more interesting filter-backtracking
. New HTMLPurifier_Injector->rewind() functionality, allows injectors to rewind
  index to reprocess tokens.
. StringHashParser now allows for multiline sections with "empty" content;
  previously the section would remain undefined.
. Added --quick option to multitest.php, which tests only the most recent
  release for each series.
. Added --distro option to multitest.php, which accepts either 'normal' or
  'standalone'. This supersedes --exclude-normal and --exclude-standalone

3.1.1, released 2008-06-19
# %URI.Munge now, by default, does not munge resources (for example, <img src="">)
  In order to enable this again, please set %URI.MungeResources to true.
! More robust imagecrash protection with height/width CSS with %CSS.MaxImgLength,
  and height/width HTML with %HTML.MaxImgLength.
! %URI.MungeSecretKey for secure URI munging. Thanks Chris
  for sponsoring this feature. Check out the corresponding documentation
  for details. (Att Nightly testers: The API for this feature changed before
  the general release. Namely, rename your directives %URI.SecureMungeSecretKey =>
  %URI.MungeSecretKey and and %URI.SecureMunge => %URI.Munge)
! Implemented post URI filtering. Set member variable $post to true to set
  a URIFilter as such.
! Allow modules to define injectors via $info_injector. Injectors are
  automatically disabled if injector's needed elements are not found.
! Support for "safe" objects added, use %HTML.SafeObject and %HTML.SafeEmbed.
  Thanks Chris for sponsoring. If you've been using ad hoc code from the
  forums, PLEASE use this instead.
! Added substitutions for %e, %n, %a and %p in %URI.Munge (in order,
  embedded, tag name, attribute name, CSS property name). See %URI.Munge
  for more details. Requested by Jochem Blok.
- Disable percent height/width attributes for img.
- AttrValidator operations are now atomic; updates to attributes are not
  manifest in token until end of operations. This prevents naughty internal
  code from directly modifying CurrentToken when they're not supposed to.
  This semantics change was requested by frank farmer.
- Percent encoding checks enabled for URI query and fragment
- Fix stray backslashes in font-family; CSS Unicode character escapes are
  now properly resolved (although *only* in font-family). Thanks Takeshi Terada
  for reporting.
- Improve parseCDATA algorithm to take into account newline normalization
- Account for browser confusion between Yen character and backslash in
  Shift_JIS encoding. This fix generalizes to any other encoding which is not
  a strict superset of printable ASCII. Thanks Takeshi Terada for reporting.
- Fix missing configuration parameter in Generator calls. Thanks vs for the
  partial patch.
- Improved adherence to Unicode by checking for non-character codepoints.
  Thanks Geoffrey Sneddon for reporting. This may result in degraded
  performance for extremely large inputs.
- Allow CSS property-value pair ''text-decoration: none''. Thanks Jochem Blok
  for reporting.
. Added HTMLPurifier_UnitConverter and HTMLPurifier_Length for convenient
  handling of CSS-style lengths. HTMLPurifier_AttrDef_CSS_Length now uses
  this class.
. API of HTMLPurifier_AttrDef_CSS_Length changed from __construct($disable_negative)
  to __construct($min, $max). __construct(true) is equivalent to
  __construct('0').
. Added HTMLPurifier_AttrDef_Switch class
. Rename HTMLPurifier_HTMLModule_Tidy->construct() to setup() and bubble method
  up inheritance hierarchy to HTMLPurifier_HTMLModule. All HTMLModules
  get this called with the configuration object.  All modules now
  use this rather than __construct(), although legacy code using constructors
  will still work--the new format, however, lets modules access the
  configuration object for HTML namespace dependant tweaks.
. AttrDef_HTML_Pixels now takes a single construction parameter, pixels.
. ConfigSchema data-structure heavily optimized; on average it uses a third
  the memory it did previously. The interface has changed accordingly,
  consult changes to HTMLPurifier_Config for details.
. Variable parsing types now are magic integers instead of strings
. Added benchmark for ConfigSchema
. HTMLPurifier_Generator requires $config and $context parameters. If you
  don't know what they should be, use HTMLPurifier_Config::createDefault()
  and new HTMLPurifier_Context().
. Printers now properly distinguish between output configuration, and
  target configuration. This is not applicable to scripts using
  the Printers for HTML Purifier related tasks.
. HTML/CSS Printers must be primed with prepareGenerator($gen_config), otherwise
  fatal errors will ensue.
. URIFilter->prepare can return false in order to abort loading of the filter
. Factory for AttrDef_URI implemented, URI#embedded to indicate URI that embeds
  an external resource.
. %URI.Munge functionality factored out into a post-filter class.
. Added CurrentCSSProperty context variable during CSS validation

3.1.0, released 2008-05-18
# Unnecessary references to objects (vestiges of PHP4) removed from method
  signatures.  The following methods do not need references when assigning from
  them and will result in E_STRICT errors if you try:
    + HTMLPurifier_Config->get*Definition() [* = HTML, CSS]
    + HTMLPurifier_ConfigSchema::instance()
    + HTMLPurifier_DefinitionCacheFactory::instance()
    + HTMLPurifier_DefinitionCacheFactory->create()
    + HTMLPurifier_DoctypeRegistry->register()
    + HTMLPurifier_DoctypeRegistry->get()
    + HTMLPurifier_HTMLModule->addElement()
    + HTMLPurifier_HTMLModule->addBlankElement()
    + HTMLPurifier_LanguageFactory::instance()
# Printer_ConfigForm's get*() functions were static-ified
# %HTML.ForbiddenAttributes requires attribute declarations to be in the
  form of tag@attr, NOT tag.attr (which will throw an error and won't do
  anything). This is for forwards compatibility with XML; you'd do best
  to migrate an %HTML.AllowedAttributes directives to this syntax too.
! Allow index to be false for config from form creation
! Added HTMLPurifier::VERSION constant
! Commas, not dashes, used for serializer IDs. This change is forwards-compatible
  and allows for version numbers like "3.1.0-dev".
! %HTML.Allowed deals gracefully with whitespace anywhere, anytime!
! HTML Purifier's URI handling is a lot more robust, with much stricter
  validation checks and better percent encoding handling. Thanks Gareth Heyes
  for indicating security vulnerabilities from lax percent encoding.
! Bootstrap autoloader deals more robustly with classes that don't exist,
  preventing class_exists($class, true) from barfing.
- InterchangeBuilder now alphabetizes its lists
- Validation error in configdoc output fixed
- Iconv and other encoding errors muted even with custom error handlers that
  do not honor error_reporting
- Add protection against imagecrash attack with CSS height/width
- HTMLPurifier::instance() created for consistency, is equivalent to getInstance()
- Fixed and revamped broken ConfigForm smoketest
- Bug with bool/null fields in Printer_ConfigForm fixed
- Bug with global forbidden attributes fixed
- Improved error messages for allowed and forbidden HTML elements and attributes
- Missing (or null) in configdoc documentation restored
- If DOM throws and exception during parsing with PH5P (occurs in newer versions
  of DOM), HTML Purifier punts to DirectLex
- Fatal error with unserialization of ScriptRequired
- Created directories are now chmod'ed properly
- Fixed bug with fallback languages in LanguageFactory
- Standalone testing setup properly with autoload
. Out-of-date documentation revised
. UTF-8 encoding check optimization as suggested by Diego
. HTMLPurifier_Error removed in favor of exceptions
. More copy() function removed; should use clone instead
. More extensive unit tests for HTMLDefinition
. assertPurification moved to central harness
. HTMLPurifier_Generator accepts $config and $context parameters during
  instantiation, not runtime
. Double-quotes outside of attribute values are now unescaped

3.1.0rc1, released 2008-04-22
# Autoload support added. Internal require_once's removed in favor of an
  explicit require list or autoloading. To use HTML Purifier,
  you must now either use HTMLPurifier.auto.php
  or HTMLPurifier.includes.php; setting the include path and including
  HTMLPurifier.php is insufficient--in such cases include HTMLPurifier.autoload.php
  as well to register our autoload handler (or modify your autoload function
  to check HTMLPurifier_Bootstrap::getPath($class)). You can also use
  HTMLPurifier.safe-includes.php for a less performance friendly but more
  user-friendly library load.
# HTMLPurifier_ConfigSchema static functions are officially deprecated. Schema
  information is stored in the ConfigSchema directory, and the
  maintenance/generate-schema-cache.php generates the schema.ser file, which
  is now instantiated. Support for userland schema changes coming soon!
# HTMLPurifier_Config will now throw E_USER_NOTICE when you use a directive
  alias; to get rid of these errors just modify your configuration to use
  the new directive name.
# HTMLPurifier->addFilter is deprecated; built-in filters can now be
  enabled using %Filter.$filter_name or by setting your own filters using
  %Filter.Custom
# Directive-level safety properties superseded in favor of module-level
  safety. Internal method HTMLModule->addElement() has changed, although
  the externally visible HTMLDefinition->addElement has *not* changed.
! Extra utility classes for testing and non-library operations can
  be found in extras/. Specifically, these are FSTools and ConfigDoc.
  You may find a use for these in your own project, but right now they
  are highly experimental and volatile.
! Integration with PHPT allows for automated smoketests
! Limited support for proprietary HTML elements, namely <marquee>, sponsored
  by Chris. You can enable them with %HTML.Proprietary if your client
  demands them.
! Support for !important CSS cascade modifier. By default, this will be stripped
  from CSS, but you can enable it using %CSS.AllowImportant
! Support for display and visibility CSS properties added, set %CSS.AllowTricky
  to true to use them.
! HTML Purifier now has its own Exception hierarchy under HTMLPurifier_Exception.
  Developer error (not enduser error) can cause these to be triggered.
! Experimental kses() wrapper introduced with HTMLPurifier.kses.php
! Finally %CSS.AllowedProperties for tweaking allowed CSS properties without
  mucking around with HTMLPurifier_CSSDefinition
! ConfigDoc output has been enhanced with version and deprecation info.
! %HTML.ForbiddenAttributes and %HTML.ForbiddenElements implemented.
- Autoclose now operates iteratively, i.e. <span><span><div> now has
  both span tags closed.
- Various HTMLPurifier_Config convenience functions now accept another parameter
  $schema which defines what HTMLPurifier_ConfigSchema to use besides the
  global default.
- Fix bug with trusted script handling in libxml versions later than 2.6.28.
- Fix bug in ExtractStyleBlocks with comments in style tags
- Fix bug in comment parsing for DirectLex
- Flush output now displayed when in command line mode for unit tester
- Fix bug with rgb(0, 1, 2) color syntax with spaces inside shorthand syntax
- HTMLPurifier_HTMLDefinition->addAttribute can now be called multiple times
  on the same element without emitting errors.
- Fixed fatal error in PH5P lexer with invalid tag names
. Plugins now get their own changelogs according to project conventions.
. Convert tokens to use instanceof, reducing memory footprint and
  improving comparison speed.
. Dry runs now supported in SimpleTest; testing facilities improved
. Bootstrap class added for handling autoloading functionality
. Implemented recursive glob at FSTools->globr
. ConfigSchema now has instance methods for all corresponding define*
  static methods.
. A couple of new historical maintenance scripts were added.
. HTMLPurifier/HTMLModule/Tidy/XHTMLAndHTML4.php split into two files
. tests/index.php can now be run from any directory.
. HTMLPurifier_Token subclasses split into separate files
. HTMLPURIFIER_PREFIX now is defined in Bootstrap.php, NOT HTMLPurifier.php
. HTMLPURIFIER_PREFIX can now be defined outside of HTML Purifier
. New --php=php flag added, allows PHP executable to be specified (command
  line only!)
. htmlpurifier_add_test() preferred method to translate test files in to
  classes, because it handles PHPT files too.
. Debugger class is deprecated and will be removed soon.
. Command line argument parsing for testing scripts revamped, now --opt value
  format is supported.
. Smoketests now cleanup after magic quotes
. Generator now can output comments (however, comments are still stripped
  from HTML Purifier output)
. HTMLPurifier_ConfigSchema->validate() deprecated in favor of
  HTMLPurifier_VarParser->parse()
. Integers auto-cast into float type by VarParser.
. HTMLPURIFIER_STRICT removed; no validation is performed on runtime, only
  during cache generation
. Reordered script calls in maintenance/flush.php
. Command line scripts now honor exit codes
. When --flush fails in unit testers, abort tests and print message
. Improved documentation in docs/dev-flush.html about the maintenance scripts
. copy() methods removed in favor of clone keyword

3.0.0, released 2008-01-06
# HTML Purifier is PHP 5 only! The 2.1.x branch will be maintained
  until PHP 4 is completely deprecated, but no new features will be added
  to it.
  + Visibility declarations added
  + Constructor methods renamed to __construct()
  + PHP4 reference cruft removed (in progress)
! CSS properties are now case-insensitive
! DefinitionCacheFactory now can register new implementations
! New HTMLPurifier_Filter_ExtractStyleBlocks for extracting <style> from
  documents and cleaning their contents up. Requires the CSSTidy library
  <http://csstidy.sourceforge.net/>. You can access the blocks with the
  'StyleBlocks' Context variable ($purifier->context->get('StyleBlocks')).
  The output CSS can also be "scoped" for a specific element, use:
  %Filter.ExtractStyleBlocksScope
! Experimental support for some proprietary CSS attributes allowed:
  opacity (and all of the browser-specific equivalents) and scrollbar colors.
  Enable by setting %CSS.Proprietary to true.
- Colors missing # but in hex form will be corrected
- CSS Number algorithm improved
- Unit testing and multi-testing now on steroids: command lines,
  XML output, and other goodies now added.
. Unit tests for Injector improved
. New classes:
  + HTMLPurifier_AttrDef_CSS_AlphaValue
  + HTMLPurifier_AttrDef_CSS_Filter
. Multitest now has a file docblock

2.1.3, released 2007-11-05
! tests/multitest.php allows you to test multiple versions by running
  tests/index.php through multiple interpreters using `phpv` shell
  script (you must provide this script!)
- Fixed poor include ordering for Email URI AttrDefs, causes fatal errors
  on some systems.
- Injector algorithm further refined: off-by-one error regarding skip
  counts for dormant injectors fixed
- Corrective blockquote definition now enabled for HTML 4.01 Strict
- Fatal error when <img> tag (or any other element with required attributes)
  has 'id' attribute fixed, thanks NykO18 for reporting
- Fix warning emitted when a non-supported URI scheme is passed to the
  MakeAbsolute URIFilter, thanks NykO18 (again)
- Further refine AutoParagraph injector. Behavior inside of elements
  allowing paragraph tags clarified: only inline content delimited by
  double newlines (not block elements) are paragraphed.
- Buggy treatment of end tags of elements that have required attributes
  fixed (does not manifest on default tag-set)
- Spurious internal content reorganization error suppressed
- HTMLDefinition->addElement now returns a reference to the created
  element object, as implied by the documentation
- Phorum mod's HTML Purifier help message expanded (unreleased elsewhere)
- Fix a theoretical class of infinite loops from DirectLex reported
  by Nate Abele
- Work around unnecessary DOMElement type-cast in PH5P that caused errors
  in PHP 5.1
- Work around PHP 4 SimpleTest lack-of-error complaining for one-time-only
  HTMLDefinition errors, this may indicate problems with error-collecting
  facilities in PHP 5
- Make ErrorCollectorEMock work in both PHP 4 and PHP 5
- Make PH5P work with PHP 5.0 by removing unnecessary array parameter typedef
. %Core.AcceptFullDocuments renamed to %Core.ConvertDocumentToFragment
  to better communicate its purpose
. Error unit tests can now specify the expectation of no errors. Future
  iterations of the harness will be extremely strict about what errors
  are allowed
. Extend Injector hooks to allow for more powerful injector routines
. HTMLDefinition->addBlankElement created, as according to the HTMLModule
  method
. Doxygen configuration file updated, with minor improvements
. Test runner now checks for similarly named files in conf/ directory too.
. Minor cosmetic change to flush-definition-cache.php: trailing newline is
  outputted
. Maintenance script for generating PH5P patch added, original PH5P source
  file also added under version control
. Full unit test runner script title made more descriptive with PHP version
. Updated INSTALL file to state that 4.3.7 is the earliest version we
  are actively testing

2.1.2, released 2007-09-03
! Implemented Object module for trusted users
! Implemented experimental HTML5 parsing mode using PH5P. To use, add
  this to your code:
        require_once 'HTMLPurifier/Lexer/PH5P.php';
        $config->set('Core', 'LexerImpl', 'PH5P');
  Note that this Lexer introduces some classes not in the HTMLPurifier
  namespace.  Also, this is PHP5 only.
! CSS property border-spacing implemented
- Fix non-visible parsing error in DirectLex with empty tags that have
  slashes inside attribute values.
- Fix typo in CSS definition: border-collapse:separate; was incorrectly
  accepted as valid CSS. Usually non-visible, because this styling is the
  default for tables in most browsers. Thanks Brett Zamir for pointing
  this out.
- Fix validation errors in configuration form
- Hammer out a bunch of edge-case bugs in the standalone distribution
- Inclusion reflection removed from URISchemeRegistry; you must manually
  include any new schema files you wish to use
- Numerous typo fixes in documentation thanks to Brett Zamir
. Unit test refactoring for one logical test per test function
. Config and context parameters in ComplexHarness deprecated: instead, edit
  the $config and $context member variables
. HTML wrapper in DOMLex now takes DTD identifiers into account; doesn't
  really make a difference, but is good for completeness sake
. merge-library.php script refactored for greater code reusability and
  PHP4 compatibility

2.1.1, released 2007-08-04
- Fix show-stopper bug in %URI.MakeAbsolute functionality
- Fix PHP4 syntax error in standalone version
. Add prefix directory to include path for standalone, this prevents
  other installations from clobbering the standalone's URI schemes
. Single test methods can be invoked by prefixing with __only

2.1.0, released 2007-08-02
# flush-htmldefinition-cache.php superseded in favor of a generic
  flush-definition-cache.php script, you can clear a specific cache
  by passing its name as a parameter to the script
! Phorum mod implemented for HTML Purifier
! With %Core.AggressivelyFixLt, <3 and similar emoticons no longer
  trigger HTML removal in PHP5 (DOMLex). This directive is not necessary
  for PHP4 (DirectLex).
! Standalone file now available, which greatly reduces the amount of
  includes (although there are still a few files that reside in the
  standalone folder)
! Relative URIs can now be transformed into their absolute equivalents
  using %URI.Base and %URI.MakeAbsolute
! Ruby implemented for XHTML 1.1
! You can now define custom URI filtering behavior, see enduser-uri-filter.html
  for more details
! UTF-8 font names now supported in CSS
- AutoFormatters emit friendly error messages if tags or attributes they
  need are not allowed
- ConfigForm's compactification of directive names is now configurable
- AutoParagraph autoformatter algorithm refined after field-testing
- XHTML 1.1 now applies XHTML 1.0 Strict cleanup routines, namely
  blockquote wrapping
- Contents of <style> tags removed by default when tags are removed
. HTMLPurifier_Config->getSerial() implemented, this is extremely useful
  for output cache invalidation
. ConfigForm printer now can retrieve CSS and JS files as strings, in
  case HTML Purifier's directory is not publicly accessible
. Introduce new text/itext configuration directive values: these represent
  longer strings that would be more appropriately edited with a textarea
. Allow newlines to act as separators for lists, hashes, lookups and
  %HTML.Allowed
. ConfigForm generates textareas instead of text inputs for lists, hashes,
  lookups, text and itext fields
. Hidden element content removal genericized: %Core.HiddenElements can
  be used to customize this behavior, by default <script> and <style> are
  hidden
. Added HTMLPURIFIER_PREFIX constant, should be used instead of dirname(__FILE__)
. Custom ChildDef added to default include list
. URIScheme reflection improved: will not attempt to include file if class
  already exists. May clobber autoload, so I need to keep an eye on it
. ConfigSchema heavily optimized, will only collect information and validate
  definitions when HTMLPURIFIER_SCHEMA_STRICT is true.
. AttrDef_URI unit tests and implementation refactored
. benchmarks/ directory now protected from public view with .htaccess file;
  run the tests via command line
. URI scheme is munged off if there is no authority and the scheme is the
  default one
. All unit tests inherit from HTMLPurifier_Harness, not UnitTestCase
. Interface for URIScheme changed
. Generic URI object to hold components of URI added, most systems involved
  in URI validation have been migrated to use it
. Custom filtering for URIs factored out to URIDefinition interface for
  maximum extensibility

2.0.1, released 2007-06-27
! Tag auto-closing now based on a ChildDef heuristic rather than a
  manually set auto_close array; some behavior may change
! Experimental AutoFormat functionality added: auto-paragraph and
  linkify your HTML input by setting %AutoFormat.AutoParagraph and
  %AutoFormat.Linkify to true
! Newlines normalized internally, and then converted back to the
  value of PHP_EOL. If this is not desired, set your newline format
  using %Output.Newline.
! Beta error collection, messages are implemented for the most generic
  cases involving Lexing or Strategies
- Clean up special case code for <script> tags
- Reorder includes for DefinitionCache decorators, fixes a possible
  missing class error
- Fixed bug where manually modified definitions were not saved via cache
  (mostly harmless, except for the fact that it would be a little slower)
- Configuration objects with different serials do not clobber each
  others when revision numbers are unequal
- Improve Serializer DefinitionCache directory permissions checks
- DefinitionCache no longer throws errors when it encounters old
  serial files that do not conform to the current style
- Stray xmlns attributes removed from configuration documentation
- configForm.php smoketest no longer has XSS vulnerability due to
  unescaped print_r output
- Printer adheres to configuration's directives on output format
- Fix improperly named form field in ConfigForm printer
. Rewire some test-cases to swallow errors rather than expect them
. HTMLDefinition printer updated with some of the new attributes
. DefinitionCache keys reordered to reflect precedence: version number,
  hash, then revision number
. %Core.DefinitionCache renamed to %Cache.DefinitionImpl
. Interlinking in configuration documentation added using
  Injector_PurifierLinkify
. Directives now keep track of aliases to themselves
. Error collector now requires a severity to be passed, use PHP's internal
  error constants for this
. HTMLPurifier_Config::getAllowedDirectivesForForm implemented, allows
  much easier selective embedding of configuration values
. Doctype objects now accept public and system DTD identifiers
. %HTML.Doctype is now constrained by specific values, to specify a custom
  doctype use new %HTML.CustomDoctype
. ConfigForm truncates long directives to keep the form small, and does
  not re-output namespaces

2.0.0, released 2007-06-20
# Completely refactored HTMLModuleManager, decentralizing safety
  information
# Transform modules changed to Tidy modules, which offer more flexibility
  and better modularization
# Configuration object now finalizes itself when a read operation is
  performed on it, ensuring that its internal state stays consistent.
  To revert this behavior, you can set the $autoFinalize member variable
  off, but it's not recommended.
# New compact syntax for AttrDef objects that can be used to instantiate
  new objects via make()
# Definitions (esp. HTMLDefinition) are now cached for a significant
  performance boost. You can disable caching by setting %Core.DefinitionCache
  to null. You CANNOT edit raw definitions without setting the corresponding
  DefinitionID directive (%HTML.DefinitionID for HTMLDefinition).
# Contents between <script> tags are now completely removed if <script>
  is not allowed
# Prototype-declarations for Lexer removed in favor of configuration
  determination of Lexer implementations.
! HTML Purifier now works in PHP 4.3.2.
! Configuration form-editing API makes tweaking HTMLPurifier_Config a
  breeze!
! Configuration directives that accept hashes now allow new string
  format: key1:value1,key2:value2
! ConfigDoc now factored into OOP design
! All deprecated elements now natively supported
! Implement TinyMCE styled whitelist specification format in
  %HTML.Allowed
! Config object gives more friendly error messages when things go wrong
! Advanced API implemented: easy functions for creating elements (addElement)
  and attributes (addAttribute) on HTMLDefinition
! Add native support for required attributes
- Deprecated and removed EnableRedundantUTF8Cleaning. It didn't even work!
- DOMLex will not emit errors when a custom error handler that does not
  honor error_reporting is used
- StrictBlockquote child definition refrains from wrapping whitespace
  in tags now.
- Bug resulting from tag transforms to non-allowed elements fixed
- ChildDef_Custom's regex generation has been improved, removing several
  false positives
. Unit test for ElementDef created, ElementDef behavior modified to
  be more flexible
. Added convenience functions for HTMLModule constructors
. AttrTypes now has accessor functions that should be used instead
  of directly manipulating info
. TagTransform_Center deprecated in favor of generic TagTransform_Simple
. Add extra protection in AttrDef_URI against phantom Schemes
. Doctype object added to HTMLDefinition which describes certain aspects
  of the operational document type
. Lexer is now pre-emptively included, with a conditional include for the
  PHP5 only version.
. HTMLDefinition and CSSDefinition have a common parent class: Definition.
. DirectLex can now track line-numbers
. Preliminary error collector is in place, although no code actually reports
  errors yet
. Factor out most of ValidateAttributes to new AttrValidator class

1.6.1, released 2007-05-05
! Support for more deprecated attributes via transformations:
  + hspace and vspace in img
  + size and noshade in hr
  + nowrap in td
  + clear in br
  + align in caption, table, img and hr
  + type in ul, ol and li
! DirectLex now preserves text in which a < bracket is followed by
  a non-alphanumeric character. This means that certain emoticons
  are now preserved.
! %Core.RemoveInvalidImg is now operational, when set to false invalid
  images will hang around with an empty src
! target attribute in a tag supported, use %Attr.AllowedFrameTargets
  to enable
! CSS property white-space now allows nowrap (supported in all modern
  browsers) but not others (which have spotty browser implementations)
! XHTML 1.1 mode now sort-of works without any fatal errors, and
  lang is now moved over to xml:lang.
! Attribute transformation smoketest available at smoketests/attrTransform.php
! Transformation of font's size attribute now handles super-large numbers
- Possibly fatal bug with __autoload() fixed in module manager
- Invert HTMLModuleManager->addModule() processing order to check
  prefixes first and then the literal module
- Empty strings get converted to empty arrays instead of arrays with
  an empty string in them.
- Merging in attribute lists now works.
. Demo script removed: it has been added to the website's repository
. Basic.php script modified to work out of the box
. Refactor AttrTransform classes to reduce duplication
. AttrTransform_TextAlign axed in favor of a more general
  AttrTransform_EnumToCSS, refer to HTMLModule/TransformToStrict.php to
  see how the new equivalent is implemented
. Unit tests now use exclusively assertIdentical

1.6.0, released 2007-04-01
! Support for most common deprecated attributes via transformations:
  + bgcolor in td, th, tr and table
  + border in img
  + name in a and img
  + width in td, th and hr
  + height in td, th
! Support for CSS attribute 'height' added
! Support for rel and rev attributes in a tags added, use %Attr.AllowedRel
  and %Attr.AllowedRev to activate
- You can define ID blacklists using regular expressions via
  %Attr.IDBlacklistRegexp
- Error messages are emitted when you attempt to "allow" elements or
  attributes that HTML Purifier does not support
- Fix segfault in unit test. The problem is not very reproduceable and
  I don't know what causes it, but a six line patch fixed it.

1.5.0, released 2007-03-23
! Added a rudimentary I18N and L10N system modeled off MediaWiki. It
  doesn't actually do anything yet, but keep your eyes peeled.
! docs/enduser-utf8.html explains how to use UTF-8 and HTML Purifier
! Newly structured HTMLDefinition modeled off of XHTML 1.1 modules.
  I am loathe to release beta quality APIs, but this is exactly that;
  don't use the internal interfaces if you're not willing to do migration
  later on.
- Allow 'x' subtag in language codes
- Fixed buggy chameleon-support for ins and del
. Added support for IDREF attributes (i.e. for)
. Renamed HTMLPurifier_AttrDef_Class to HTMLPurifier_AttrDef_Nmtokens
. Removed context variable ParentType, replaced with IsInline, which
  is false when you're not inline and an integer of the parent that
  caused you to become inline when you are (so possibly zero)
. Removed ElementDef->type in favor of ElementDef->descendants_are_inline
  and HTMLDefinition->content_sets
. StrictBlockquote now reports what elements its supposed to allow,
  rather than what it does allow
. Removed HTMLDefinition->info_flow_elements in favor of
  HTMLDefinition->content_sets['Flow']
. Removed redundant "exclusionary" definitions from DTD roster
. StrictBlockquote now requires a construction parameter as if it
  were an Required ChildDef, this is the "real" set of allowed elements
. AttrDef partitioned into HTML, CSS and URI segments
. Modify Youtube filter regexp to be multiline
. Require both PHP5 and DOM extension in order to use DOMLex, fixes
  some edge cases where a DOMDocument class exists in a PHP4 environment
  due to DOM XML extension.

1.4.1, released 2007-01-21
! docs/enduser-youtube.html updated according to new functionality
- YouTube IDs can have underscores and dashes

1.4.0, released 2007-01-21
! Implemented list-style-image, URIs now allowed in list-style
! Implemented background-image, background-repeat, background-attachment
  and background-position CSS properties. Shorthand property background
  supports all of these properties.
! Configuration documentation looks nicer
! Added %Core.EscapeNonASCIICharacters to workaround loss of Unicode
  characters while %Core.Encoding is set to a non-UTF-8 encoding.
! Support for configuration directive aliases added
! Config object can now be instantiated from ini files
! YouTube preservation code added to the core, with two lines of code
  you can add it as a filter to your code. See smoketests/preserveYouTube.php
  for sample code.
! Moved SLOW to docs/enduser-slow.html and added code examples
- Replaced version check with functionality check for DOM (thanks Stephen
  Khoo)
. Added smoketest 'all.php', which loads all other smoketests via frames
. Implemented AttrDef_CSSURI for url(http://google.com) style declarations
. Added convenient single test selector form on test runner

1.3.2, released 2006-12-25
! HTMLPurifier object now accepts configuration arrays, no need to manually
  instantiate a configuration object
! Context object now accessible to outside
! Added enduser-youtube.html, explains how to embed YouTube videos. See
  also corresponding smoketest preserveYouTube.php.
! Added purifyArray(), which takes a list of HTML and purifies it all
! Added static member variable $version to HTML Purifier with PHP-compatible
  version number string.
- Fixed fatal error thrown by upper-cased language attributes
- printDefinition.php: added labels, added better clarification
. HTMLPurifier_Config::create() added, takes mixed variable and converts into
  a HTMLPurifier_Config object.

1.3.1, released 2006-12-06
! Added HTMLPurifier.func.php stub for a convenient function to call the library
- Fixed bug in RemoveInvalidImg code that caused all images to be dropped
  (thanks to .mario for reporting this)
. Standardized all attribute handling variables to attr, made it plural

1.3.0, released 2006-11-26
# Invalid images are now removed, rather than replaced with a dud
  <img src="" alt="Invalid image" />. Previous behavior can be restored
  with new directive %Core.RemoveInvalidImg set to false.
! (X)HTML Strict now supported
  + Transparently handles inline elements in block context (blockquote)
! Added GET method to demo for easier validation, added 50kb max input size
! New directive %HTML.BlockWrapper, for block-ifying inline elements
! New directive %HTML.Parent, allows you to only allow inline content
! New directives %HTML.AllowedElements and %HTML.AllowedAttributes to let
  users narrow the set of allowed tags
! <li value="4"> and <ul start="2"> now allowed in loose mode
! New directives %URI.DisableExternalResources and %URI.DisableResources
! New directive %Attr.DisableURI, which eliminates all hyperlinking
! New directive %URI.Munge, munges URI so you can use some sort of redirector
  service to avoid PageRank leaks or warn users that they are exiting your site.
! Added spiffy new smoketest printDefinition.php, which lets you twiddle with
  the configuration settings and see how the internal rules are affected.
! New directive %URI.HostBlacklist for blocking links to bad hosts.
  xssAttacks.php smoketest updated accordingly.
- Added missing type to ChildDef_Chameleon
- Remove Tidy option from demo if there is not Tidy available
. ChildDef_Required guards against empty tags
. Lookup table HTMLDefinition->info_flow_elements added
. Added peace-of-mind variable initialization to Strategy_FixNesting
. Added HTMLPurifier->info_parent_def, parent child processing made special
. Added internal documents briefly summarizing future progression of HTML
. HTMLPurifier_Config->getBatch($namespace) added
. More lenient casting to bool from string in HTMLPurifier_ConfigSchema
. Refactored ChildDef classes into their own files

1.2.0, released 2006-11-19
# ID attributes now disabled by default. New directives:
  + %HTML.EnableAttrID - restores old behavior by allowing IDs
  + %Attr.IDPrefix - %Attr.IDBlacklist alternative that munges all user IDs
    so that they don't collide with your IDs
  + %Attr.IDPrefixLocal - Same as above, but for when there are multiple
    instances of user content on the page
  + Profuse documentation on how to use these available in docs/enduser-id.txt
! Added MODx plugin <http://modxcms.com/forums/index.php/topic,6604.0.html>
! Added percent encoding normalization
! XSS attacks smoketest given facelift
! Configuration documentation now has table of contents
! Added %URI.DisableExternal, which prevents links to external websites.  You
  can also use %URI.Host to permit absolute linking to subdomains
! Non-accessible resources (ex. mailto) blocked from embedded URIs (img src)
- Type variable in HTMLDefinition was not being set properly, fixed
- Documentation updated
  + TODO added request Phalanger
  + TODO added request Native compression
  + TODO added request Remove redundant tags
  + TODO added possible plaintext formatter for HTML Purifier documentation
  + Updated ConfigDoc TODO
  + Improved inline comments in AttrDef/Class.php, AttrDef/CSS.php
    and AttrDef/Host.php
  + Revamped documentation into HTML, along with misc updates
- HTMLPurifier_Context doesn't throw a variable reference error if you attempt
  to retrieve a non-existent variable
. Switched to purify()-wide Context object registry
. Refactored unit tests to minimize duplication
. XSS attack sheet updated
. configdoc.xml now has xml:space attached to default value nodes
. Allow configuration directives to permit null values
. Cleaned up test-cases to remove unnecessary swallowErrors()

1.1.2, released 2006-09-30
! Add HTMLPurifier.auto.php stub file that configures include_path
- Documentation updated
  + INSTALL document rewritten
  + TODO added semi-lossy conversion
  + API Doxygen docs' file exclusions updated
  + Added notes on HTML versus XML attribute whitespace handling
  + Noted that HTMLPurifier_ChildDef_Custom isn't being used
  + Noted that config object's definitions are cached versions
- Fixed lack of attribute parsing in HTMLPurifier_Lexer_PEARSax3
- ftp:// URIs now have their typecodes checked
- Hooked up HTMLPurifier_ChildDef_Custom's unit tests (they weren't being run)
. Line endings standardized throughout project (svn:eol-style standardized)
. Refactored parseData() to general Lexer class
. Tester named "HTML Purifier" not "HTMLPurifier"

1.1.1, released 2006-09-24
! Configuration option to optionally Tidy up output for indentation to make up
  for dropped whitespace by DOMLex (pretty-printing for the entire application
  should be done by a page-wide Tidy)
- Various documentation updates
- Fixed parse error in configuration documentation script
- Fixed fatal error in benchmark scripts, slightly augmented
- As far as possible, whitespace is preserved in-between table children
- Sample test-settings.php file included

1.1.0, released 2006-09-16
! Directive documentation generation using XSLT
! XHTML can now be turned off, output becomes <br>
- Made URI validator more forgiving: will ignore leading and trailing
  quotes, apostrophes and less than or greater than signs.
- Enforce alphanumeric namespace and directive names for configuration.
- Table child definition made more flexible, will fix up poorly ordered elements
. Renamed ConfigDef to ConfigSchema

1.0.1, released 2006-09-04
- Fixed slight bug in DOMLex attribute parsing
- Fixed rejection of case-insensitive configuration values when there is a
  set of allowed values.  This manifested in %Core.Encoding.
- Fixed rejection of inline style declarations that had lots of extra
  space in them.  This manifested in TinyMCE.

1.0.0, released 2006-09-01
! Shorthand CSS properties implemented: font, border, background, list-style
! Basic color keywords translated into hexadecimal values
! Table CSS properties implemented
! Support for charsets other than UTF-8 (defined by iconv)
! Malformed UTF-8 and non-SGML character detection and cleaning implemented
- Fixed broken numeric entity conversion
- API documentation completed
. (HTML|CSS)Definition de-singleton-ized

1.0.0beta, released 2006-08-16
! First public release, most functionality implemented. Notable omissions are:
  + Shorthand CSS properties
  + Table CSS properties
  + Deprecated attribute transformations

    vim: et sw=4 sts=4