<script type="text/javascript" language="javascript">    
e=document.getElementsByTagName("TD");    
for(k=15; k<e.length;k++) {    
if(e[k].className=='posttdMessage') {    
s=e[k].innerHTML;    
while (s.indexOf('[off ]') != -1){    
s=s.replace('[off ]','<fieldset><legend><font style="font-size: 10px; font-family: Verdana; color: grey;"> Оффтоп</font></legend><font style="font-size: 11px; font-family: Verdana; color: grey;">'); s=s.replace('[/off ]','</font></fieldset>');    
e[k].innerHTML=s;    
}    
} }    
</script>

<input accesskey="y" value="off" onclick="simpletag('off','','','message',''); return false;" class="codeButtons" title="Оффтоп" name="offtop" type="button">