browserName = navigator.appName;   // detect browser 
           browserVer = parseInt(navigator.appVersion);

  if ((browserName == "Netscape" && browserVer >= 3) ||
                 (browserName == "Microsoft Internet Explorer" && browserVer >= 4))
                 version = "n3";
                 else version = "n2";

               if (version == "n3") {         
               nav1on = new Image();           
               nav1on.src = "/nav_images/about2.gif";     
               nav2on = new Image(); 
               nav2on.src = "/nav_images/news2.gif";
               nav3on = new Image(); 
               nav3on.src = "/nav_images/ourlabs2.gif";
               nav4on = new Image(); 
               nav4on.src = "/nav_images/markets2.gif";
			   nav5on = new Image(); 
               nav5on.src = "/nav_images/rfq2.gif";
			   nav6on = new Image(); 
               nav6on.src = "/nav_images/library2.gif";
			   nav7on = new Image(); 
               nav7on.src = "/nav_images/customer2.gif";
			  
               nav1off = new Image();         // preload images activated 
               nav1off.src = "/nav_images/about.gif";  // when mouse moves off menu 
               nav2off = new Image();
               nav2off.src = "/nav_images/news.gif";
               nav3off = new Image();
               nav3off.src = "/nav_images/ourlabs.gif";
			   nav4off = new Image();
               nav4off.src = "/nav_images/markets.gif";
			   nav5off = new Image();
               nav5off.src = "/nav_images/rfq.gif";
			   nav6off = new Image();
               nav6off.src = "/nav_images/library.gif";
			   nav7off = new Image();
               nav7off.src = "/nav_images/customer.gif";

               }

function img_act(imgName) {
        if (version == "n3") {
        imgOn = eval(imgName + "on.src");
        document [imgName].src = imgOn;
        }
}

function img_inact(imgName) {
        if (version == "n3") {
        imgOff = eval(imgName + "off.src");
        document [imgName].src = imgOff;
        }
}