Highlight

HighlightExtension adds ==marked text== as a small inline syntax. It renders the marked content with the semantic HTML <mark> element.

Install

HighlightExtension is bundled with alto/markdown:

composer require alto/markdown

Configure

Add the extension to any factory profile:

<?php

use Alto\Markdown\Extension\Highlight\HighlightExtension;
use Alto\Markdown\Markdown;

$markdown = Markdown::github()->with(new HighlightExtension());

Markdown

Review the ==important change== before merging.

HTML

<p>Review the <mark>important change</mark> before merging.</p>

Options

This extension has no configuration options.

Security

The extension grants no resource or raw HTML authority. Highlighted content is stored as plain text and HTML-sensitive characters are escaped during output.

Behavior

The opening and closing == delimiters must appear on the same line. The content cannot start or end with whitespace, and an empty pair stays literal.

Highlighted content is plain text. Markdown syntax inside the delimiters is not parsed, and HTML-sensitive characters are escaped:

==**important** and <safe>==

<p><mark>**important** and &lt;safe&gt;</mark></p>

Escaped delimiters and delimiters inside code spans remain literal.