function addEvent(obj, evType, fn){ 
	if (obj.addEventListener){ 
		obj.addEventListener(evType, fn, false); 
		return true; 
	}
	else if (obj.attachEvent){ 
		var r = obj.attachEvent("on"+evType, fn); 
		return r; 
	}
	else { 
		//alert("Handler could not be added");
		return false; 
	} 
}
function removeEvent(obj, evType, fn){
	if (obj.removeEventListener){
		obj.removeEventListener(evType, fn, false);
		return true;
	}
	else if (obj.detachEvent){
		var r = obj.detachEvent("on"+evType, fn);
		return r;
	}
	else {
		//alert("Handler could not be removed");
		return false; 
	}
}