function newImage(arg) {
	if (document.images) {
		rslt = new Image();
		rslt.src = arg;
		return rslt;
	}
}

function changeImages() {
	if (document.images && (preloadFlag == true)) {
		for (var i=0; i<changeImages.arguments.length; i+=2) {
			document[changeImages.arguments[i]].src = changeImages.arguments[i+1];
		}
	}
}

var preloadFlag = false;
function preloadImages() {
	if (document.images) {
		nav_cushion_over = newImage("images/nav_cushion-over.gif");
		nav_modu_over = newImage("images/nav_modu-over.gif");
		nav_anchor_over = newImage("images/nav_anchor-over.gif");
		nav_contact_over = newImage("images/nav_contact-over.gif");
		preloadFlag = true;
	}
}

function hideLayer(layerName)
{
   if (document.getElementById) 
   {
       var targetElement = document.getElementById(layerName);
       targetElement.style.visibility = 'hidden';
   }
}