if (document.images) {
	n1on = new Image();    n1on.src = "images/nav1-on.gif";
	n2on = new Image();    n2on.src = "images/nav2-on.gif";
	n3on = new Image();    n3on.src = "images/nav3-on.gif";
	n4on = new Image();    n4on.src = "images/nav4-on.gif";
	n5on = new Image();    n5on.src = "images/nav5-on.gif";
	n6on = new Image();    n6on.src = "images/nav6-on.gif";
}

function imgOn(imgName) {
	if (document.images) {
		oSrc=document[imgName].src;
		document[imgName].src = eval(imgName + "on.src");
	}
}
function imgOff(imgName) {
	if(oSrc){
		document[imgName].src = oSrc;
	}
}