if (document.images) {

	nav1on = new Image();   nav1on.src = "images/nav_1b.gif";
	nav1off = new Image();   nav1off.src = "images/nav_1a.gif";

	nav2on = new Image();   nav2on.src = "images/nav_2b.gif";
	nav2off = new Image();   nav2off.src = "images/nav_2a.gif";
            
	nav3on = new Image();   nav3on.src = "images/nav_3b.gif";
	nav3off = new Image();   nav3off.src = "images/nav_3a.gif";

	nav4on = new Image();   nav4on.src = "images/nav_4b.gif";
	nav4off = new Image();   nav4off.src = "images/nav_4a.gif";
	
	nav5on = new Image();   nav5on.src = "images/nav_5b.gif";
	nav5off = new Image();   nav5off.src = "images/nav_5a.gif";
	
	nav6on = new Image();   nav6on.src = "images/nav_6b.gif";
	nav6off = new Image();   nav6off.src = "images/nav_6a.gif";
	
	nav7on = new Image();   nav7on.src = "images/nav_7b.gif";
	nav7off = new Image();   nav7off.src = "images/nav_7a.gif";

	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");        
		}
	}
	
}