document.attachEventListener = function(object, eventName, func)
{
	if(object == null)
	{
		alert("attachEventListener error:\n\ntarget of event can't be null");
		return;
	}

	if(document.attachEvent != null)
	{
		object.attachEvent(eventName, func);
	}
	else
	{
		object.addEventListener(eventName.substring(2, eventName.length), func, true);
	}
}

document.detachEventListener = function(object, eventName, func)
{
	if(object == null)
	{
		alert("detachEventListener error:\n\ntarget of event can't be null");
		return;
	}

	if(document.detachEvent != null)
	{
		object.detachEvent(eventName, func);
	}
	else
	{
		object.removeEventListener(eventName.substring(2, eventName.length), func, false);
	}
}