PHP can be mixed with HTML. The PHP stuff has to be inside the "<? ?>" tags. The HTML is OUTSIDE these tags.
For example:
<?
// PHP...
echo "Generated: ".date('m/d/Y', mktime())";
?>
<!-- HTML NOW -->
<h3> Priority Report </h3>
<!-- BEGIN JSCRIPT
blah blah blah
END JSCRIPT -->
<?
// now we're back in PHP
echo "Done. ";
?>
For larger projects, mixing HTML and PHP like this gets very painful. Consider using something like PHPLib templates to separate the HTML and the PHP code so that you can separate the logic of PHP from the presentation. (HTML)