browserName = navigator.appName;
browserVer = parseInt(navigator.appVersion);
if ((browserName == "Netscape" && browserVer >= 3) ||
(browserName == "Microsoft Internet Explorer" && browserVer >=4)) version =
"n3";
else version = "n2"
             if (version == "n3") {
             toc1on = new Image();
             toc1on.src = "images/toc1on.gif";
             toc2on = new Image();
             toc2on.src = "images/toc2on.gif";
             toc3on = new Image();
             toc3on.src = "images/toc3on.gif";
             toc4on = new Image();
             toc4on.src = "images/toc4on.gif";
             toc5on = new Image();
             toc5on.src = "images/toc5on.gif";


             toc1off = new Image();
             toc1off.src = "images/toc1off.gif";
             toc2off = new Image();
             toc2off.src = "images/toc2off.gif";
             toc3off = new Image();
             toc3off.src = "images/toc3off.gif";
             toc4off = new Image();
             toc4off.src = "images/toc4off.gif";
             toc5off = new Image();
             toc5off.src = "images/toc5off.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;
             }

     }