//add event function
function addEvent(obj, evType, fn)
{
 if (obj.addEventListener){
   obj.addEventListener(evType, fn, true);
   return true;
 }
 else if (obj.attachEvent)
 {
   var r = obj.attachEvent("on"+evType, fn);
   return r;
 }
 else
 {
   return false;
 }
}