<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
            "http://www.w3.org/TR/html4/strict.dtd">

<p><b>This should have a p tag</b></p>
<!--This is a comment -->

<div>This shouldn't</div>

<?php echo "block_level";?>

<p>&lt;?php echo "not_block_level";?&gt;</p>