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

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

if (document.images){
	networkingOn = new Image();
	networkingOn.src = "img/nav_networking_hi.gif";
	networkingOff = new Image();
	networkingOff.src = "img/nav_networking.gif";
	
	swdevOn = new Image();
	swdevOn.src = "img/nav_swdev_hi.gif";
	swdevOff = new Image();
	swdevOff.src = "img/nav_swdev.gif";
	
	electronicsOn = new Image();
	electronicsOn.src = "img/nav_electronics_hi.gif";
	electronicsOff = new Image();
	electronicsOff.src = "img/nav_electronics.gif";
	
	militaryOn = new Image();
	militaryOn.src = "img/nav_military_hi.gif";
	militaryOff = new Image();
	militaryOff.src = "img/nav_military.gif";
	
	formOn = new Image();
	formOn.src = "img/nav_form_hi.gif";
	formOff = new Image();
	formOff.src = "img/nav_form.gif";
	
}