<?php
$UNSAFE_HTML = array(
    "!javascript\s*:!is",
    "!vbscri?pt\s*:!is",
    "!<\s*embed.*swf!is",
    "!vbscri?pt\s*:!is",
    "!<.*[^a-z]onabort\s*=!is",
    "!<.*[^a-z]onblur\s*=!is",
    "!<.*[^a-z]onchange\s*=!is",
    "!<.*[^a-z]onfocus\s*=!is",
    "!<.*[^a-z]onmouseout\s*=!is",
    "!<.*[^a-z]onmouseover\s*=!is",
    "!<.*[^a-z]onload\s*=!is",
    "!<.*[^a-z]onreset\s*=!is",
    "!<.*[^a-z]onselect\s*=!is",
    "!<.*[^a-z]onsubmit\s*=!is",
    "!<.*[^a-z]onunload\s*=!is",
    "!<.*[^a-z]onerror\s*=!is",
    "!<.*[^a-z]onclick\s*=!is"
);

function unsafe_html($html) {
    global $UNSAFE_HTML;

    foreach ($UNSAFE_HTML as $match) {
        if (preg_match($match, $html, 
                        $matches)) {
            return $match;
        }
    }
    return false;
}
?>