detect blocker script

<div id="ad"><!-- ad code //--></div>
<script type="text/javascript">
function detectBlocker() {
    if ($('#ad').height() == 0 || $('#ad').filter(':visible').length == 0 || $('#ad').filter(':hidden').length > 0) {
        $('#ad').prepend('<div class="alert alert-info"><p><strong>You are using an Adblocker!</strong> This is a private, non-commercial website. If you like it please consider to donate or to <a href="abp:subscribe?location=http%3A%2F%2Flastfm.dontdrinkandroot.net%2Funblock.txt&amp;title=Last.fm%20Tools">unblock</a> it.</p></div>');
    }
}
</script>