Pound #

# is character, used in various situations:

• Starts a single line comment

• Starts the anchor part of a URL

This is also called a hash, although hash as many other meanings.

<?php

    parse_url('http://www.php.net/strlen#anchor');

    # A single line PHP comment

?>

Documentation

Related : Comments, Slash /, Universal Resource Locator (URL), Anchor, Hash