api.HTMLElement.focus - incompabile behaviour on input elements

[aadcg]

What type of issue is this?

Browser bug (a bug with a feature that may impact site compatibility)

What information was incorrect, unhelpful, or incomplete?

I've noticed that on WebKitGTK calling focus also selects the value of input elements. On Firefox, you're required to call focus and select.

What browsers does this problem apply to, if applicable?

Safari

What did you expect to see?

As per the spec, it seems that focus shouldn't select.

Did you test this? If so, how?

Tested on WebKitGTK and Firefox.

<input id="myTextField" value="Text field." />
<button id="focusButton">Click to set focus on the text field</button>

document.getElementById("focusButton").addEventListener("click", () => {
  document.getElementById("myTextField").focus();
});

Can you link to any release notes, bugs, pull requests, or MDN pages related to this?

No response

Do you have anything more you want to share?

No response

MDN URL

https://developer.mozilla.org/en-US/docs/Web/API/HTMLElement/focus

MDN metadata

MDN page report details

• Query: api.HTMLElement.focus
• Report started: 2025-02-16T17:49:19.301Z

[caugner]

This seems to have already been reported in the WebKit bug tracker: https://bugs.webkit.org/show_bug.cgi?id=56820

Verified with this MDN Playground.

The behavior might be caused by these lines in the WebKit source: https://github.com/WebKit/WebKit/blob/c638de65783f7bdc50e27c165eac138956d000d6/Source/WebCore/dom/Element.cpp#L4077-L4084

Note that the observed behavior is similar to tabbing into the input field, in which case all browsers seem to select the value.

[caugner]

For now, we could add a note on the Safari support statement for api.HTMLElement.focus:

On editable elements, the value is selected as a side-effect.

[aadcg]

@caugner thanks for confirming and adding those pieces of information.

For now, we could add a note on the Safari support statement for api.HTMLElement.focus:

I have never contributed to MDN. Since this is a trivial change, I'd prefer if you'd went ahead and created a PR. Otherwise, I'd need to get acquainted with the project and the contribution process.