function addEventHandler(object,event,handler)
{
	if ((object==null)||(event==null)||(handler==null))
		return;
		
	if (object.attachEvent)
		object.attachEvent("on"+event,handler);
	else
		object.addEventListener(event,handler,false);
}

function removeEventHandler(object,event,handler)
{
	if ((object==null)||(event==null)||(handler==null))
		return;
		
	if (object.detachEvent)
		object.detachEvent("on"+event,handler);
	else
		object.removeEventListener(event,handler,false);
}

function eventSrcElement(e)
{
	if (typeof(e.srcElement)=="undefined")
		return e.target;
	else
		return e.srcElement;
}

function firstElement(el)
{
	return el.firstChild;
}

function nextSiblingElement(el)
{
	while (true)
	{
		el=el.nextSibling;
		if (el==null)
			return null;
		return el;
	}
}