function addEvent( obj, type, fn )
{
   if (obj.addEventListener)
   {
      obj.addEventListener( type, fn, false );
   }
   else if (obj.attachEvent)
   {
      obj["e"+type+fn] = fn;
      obj[type+fn] = function() { obj["e"+type+fn]( window.event ); }
      obj.attachEvent( "on"+type, obj[type+fn] );
   }
}

function removeEvent( obj, type, fn )
{
	if (obj.removeEventListener)
	{
		obj.removeEventListener( type, fn, false );
	}
	else if (obj.detachEvent)
	{
		obj.detachEvent( "on"+type, obj[type+fn] );
		obj[type+fn] = null;
		obj["e"+type+fn] = null;
	}
}