PHP Manual: Syntax highlighting of a string

Description

stringtrue highlight_string(string $string, bool $return = false)

Outputs or returns html markup for a syntax highlighted version of the given PHP code using the colors defined in the built-in syntax highlighter for PHP.

Parameters

string: The PHP code to be highlighted. This should include the opening tag.
return: Set this parameter to true to make this function return the highlighted code.

Return Values

If return is set to true, returns the highlighted code as a string instead of printing it out. Otherwise, it will return true.

Changelog

Version	Description
8.4.0	Return type changed from stringbool to stringtrue.
8.3.0	The resulting HTML has changed.

Examples

Example #1 highlight_string example

<?php
highlight_string('<?php phpinfo(); ?>');
?>

The above example will output:

<code><span style="color: #000000">
<span style="color: #0000BB">&lt;?php phpinfo</span><span style="color: #007700">(); </span><span style="color: #0000BB">?&gt;</span>
</span>
</code>

Output of the above example in PHP 8.3:

<pre><code style="color: #000000"><span style="color: #0000BB">&lt;?php phpinfo</span><span style="color: #007700">(); </span><span style="color: #0000BB">?&gt;</span></code></pre>

Notes

Note:
When the return parameter is used, this function uses internal output buffering so it cannot be used inside an ob_start callback function.

The HTML markup generated is subject to change.

highlight_string