window.onload=function(){	 
	 findNavlinks();	 
}

function findNavlinks(){
	var navLinks;
	if(document.getElementById("nav2")){
		navLinks = document.getElementById("nav2").getElementsByTagName("a");
		addEventsToLinks(navLinks);
	}	
}

function addEventsToLinks(nvLnks){
	for(var i=0; i < nvLnks.length; i++){		
		nvLnks[i].onmouseover=function(){
			showTooltip(this.id);
		};		
		nvLnks[i].onmouseout=function(){
			hideTooltip(this.id);
		};
	}
}

function showTooltip(obj){
	var formSelect = document.getElementsByTagName("select");
	if(formSelect.length >= 1){
		formSelect[0].style.visibility = "hidden";
	}	
	var linkNr = obj.replace('onderwerp','');
	var tooltip = "tooltip_" + linkNr;
	document.getElementById(tooltip).style.top = getAbsoluteTop(obj) - 140 +'px';	
	document.getElementById(tooltip).style.visibility = "visible";
}

function hideTooltip(obj){	
	var formSelect = document.getElementsByTagName("select");
	if(formSelect.length >= 1){
		formSelect[0].style.visibility = "visible";
	}
	var linkNr = obj.replace('onderwerp','');
	var tooltip = "tooltip_" + linkNr;
	document.getElementById(tooltip).style.visibility = "hidden";
}

function getAbsoluteTop(objectId) {
	var o = document.getElementById(objectId);
	var oTop = o.offsetTop;
	while(o.offsetParent!=null) { 
		var oParent = o.offsetParent;
		oTop += oParent.offsetTop;
		o = oParent;
	}
	return oTop;
}