ALS Highlight — demo

Quick visual check that highlighting and UI options work as expected.

Theme: Line numbers “Wrap” button “Copy” button maxWidth maxHeight padding

JavaScript — common & edge cases

Numbers (hex/bin/oct/bigint/exp), literals, classes/extends, arrows, optional chaining, compound ops, regex contexts.

CSS — selectors, attributes, functions, colors

Pseudo-classes/elements, combinators, attribute selectors and operators, @media prelude, hex colors (3/4/6/8), numbers/units, functions with commas, !important.

HTML — tags/attrs, comments/CDATA, embedded JS/CSS

Tag/attribute highlighting and delegation into JS/CSS inside <script>/<style>. Also checks <!doctype>, comments and CDATA.

Fallback & sandbox

Unknown language (fallback)

Should render “as-is” with HTML entities escaped.

Sandbox

Paste any code and pick a language. It renders using the current options above.

Lang:

Using global IIFE bundle: index.js → exposes window.Highlighter. Works even from file:// — no servers/build tools required.