katex-header.html

<!-- Credit: https://stackoverflow.com/a/54573800 -->
<!-- Credit: https://github.com/m-ou-se/rust-horrible-katex-hack/blob/master/src/lib.rs -->

<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/katex@0.13.11/dist/katex.min.css" integrity="sha384-Um5gpz1odJg5Z4HAmzPtgZKdTBHZdw8S29IecapCSB31ligYPhHQZMIlWLYQGVoc" crossorigin="anonymous">

<script defer src="https://cdn.jsdelivr.net/npm/katex@0.13.11/dist/katex.min.js" integrity="sha384-YNHdsYkH6gMx9y3mRkmcJ2mFUjTd0qNQQvY9VYZgQd7DcN7env35GzlmFaZ23JGp" crossorigin="anonymous"></script>

<script>
    document.addEventListener("DOMContentLoaded", () => {
        let codes = [...document.getElementsByTagName("code")];
        for (let code of codes) {
            if (code.classList.contains("language-math")) {
                let p = document.createElement("p");
                katex.render(code.textContent, p, { displayMode: true });
                let pre = code.parentNode;
                pre.parentNode.replaceChild(p, pre);
            } else if (/^\$.*\$$/.test(code.textContent)) {
                let span = document.createElement("span");
                katex.render(code.textContent.slice(1, -1), span);
                code.parentNode.replaceChild(span, code);
            }
        }
    });
</script>