browserName = navigator.appName;
browserVersion = parseInt(navigator.appVersion);
   if (browserName == "Netscape" && browserVersion >= 3) version = "n3";
   else if (browserName == "Microsoft Internet Explorer" && browserVersion >= 4) version = "n3";
   else version= "n2";

        if (version == "n3") {

        home = new Image(65,45)
        home.src = "/images/tab_home.gif"							//default btn				//default btn src
       	home_down = new Image(65,45)					//replace btn
        home_down.src = "/images/tab_home_over.gif"				//replace btn src

        sales = new Image(106,45)							//default btn
        sales.src = "/images/tab_sales.gif"					//default btn src
       	sales_down = new Image(106,45)						//replace btn
        sales_down.src = "/images/tab_sales_over.gif"				//replace btn src

        svc = new Image(106,45)							//default btn
        svc.src = "/images/tab_svc.gif"					//default btn src
       	svc_down = new Image(106,45)						//replace btn
        svc_down.src = "/images/tab_svc_over.gif"				//replace btn src

        install = new Image(106,45)							//default btn
        install.src = "/images/tab_install.gif"					//default btn src
       	install_down = new Image(106,45)						//replace btn
        install_down.src = "/images/tab_install_over.gif"				//replace btn src
        
        exchange = new Image(106,45)							//default btn
        exchange.src = "/images/tab_exchange.gif"					//default btn src
       	exchange_down = new Image(106,45)						//replace btn
        exchange_down.src = "/images/tab_exchange_over.gif"				//replace btn src
        
        }

function buttonOn(imageName) {
         if (version == "n3") {
                img=eval(imageName+"_down.src")
                document[imageName].src=img
                }
        }

function buttonOff(imageName) {
        if (version == "n3") {
                img=eval(imageName+".src")
                document[imageName].src=img
                }
        }