php how to comment out code code example

Example 1: comment in php

It is worth mentioning that, HTML comments have no meaning in PHP parser. So,

<!-- comment
<?php echo some_function(); ?>
-->

WILL execute some_function() and echo result inside HTML comment.

Example 2: comment in php

<h1>This is an <?php # echo 'simple';?> example</h1>
<p>The header above will say 'This is an  example'.</p>