found it somewhere But Its Damm cool
javascript:f=prompt('Put your Commentz here:','');cmm=location.href.match(/cmm.*/);tid=location.href.match(/tid=\d*/);a=document.forms[1];;a=document.forms[1];a.action='/CommMsgPost.aspx?'+cmm+'&'+tid+'&bodyText='+f+'&Action.submit';a.submit();void(0)
open Topic , past script In web address Bar Hit enter type Your message in new opened Box hit enter Done