function SwitchMenu(numb){
	whichA = "arrow" + numb;
	arrowR = new Image(); arrowR.src = "page_images/arrow_right.gif";
	arrowD = new Image(); arrowD.src = "page_images/arrow_down.gif";
	obj = "sub" + numb;
	if(document.getElementById){
	var el = document.getElementById(obj);
	var ar = document.getElementById("nav").getElementsByTagName("UL");
		if(el.style.display == "none"){
			for (var i=0; i<ar.length; i++){
				ar[i].style.display = "none";
				document.images['arrow'+(i+1)].src = arrowR.src;
			}
			el.style.display = "block";
			document.images[whichA].src = arrowD.src;
		}else{
			el.style.display = "none";
			document.images[whichA].src = arrowR.src;
		}
	}
}
document.onselectstart = new Function("return true");