function MM_swapimg(divName, totalImgs) {
	for (var i=1; i<=totalImgs; i++) {
		var showDivName = 'img_' + i;
		var showObj = document.getElementById(showDivName);
		var fadeDuration= 1000;
		if (showDivName == divName)
			showObj.style.visibility = 'visible';
		else
			showObj.style.visibility = 'hidden';
		}
	}
<!--navbar-->	
sfHover = function() {
	var sfEls = document.getElementById("nav").getElementsByTagName("LI");
	for (var i=1; i<sfEls.length; i++) {
		sfEls[i].onmouseover=function() {
			this.className+=" sfhover";
		}
		sfEls[i].onmouseout=function() {
			this.className=this.className.replace(new RegExp(" sfhover\\b"), "");
		}
	}
}
if (window.attachEvent) window.attachEvent("onload", sfHover);