function objRef(id) {if (document.getElementById(id)) return document.getElementById(id)}
function styleRef(id) {return this.objRef(id).style}

function hl(obj){
           b=obj.src;
           s=(b.substring(b.length-4,b.length-5)==0)?'1':'0';
           obj.src=(b.substring(b.length-5,0)+s+b.substring(b.length,b.length-4));
}	

/* geeft hoogste Z-index op pagina van ALLE elementen (werkt niet in Chrome!) */
function highestZindex(){
	var allElems = document.getElementsByTagName? document.getElementsByTagName("*"): document.all; // or test for that too
	var maxZIndex = 0;
	for(var i=0;i<allElems.length;i++) {
		var elem = allElems[i];
		var cStyle = null;
		if (elem.currentStyle) {
			cStyle = elem.currentStyle;
		} else if (document.defaultView && document.defaultView.getComputedStyle) {
			cStyle = document.defaultView.getComputedStyle(elem,"");
		}
		var sNum;
		if (cStyle) {
			sNum = Number(cStyle.zIndex);
		} else {
			sNum = Number(elem.style.zIndex);
		}
		if (!isNaN(sNum)) {
			maxZIndex = Math.max(maxZIndex,sNum);
		}
	}
	return maxZIndex;
}