if ((navigator.appName == "Netscape" && parseInt(navigator.appVersion) >= 3) || (navigator.appName == "Microsoft Internet Explorer" && parseInt(navigator.appVersion) >=4)) jv="Enabled";
       else jv = "Disabled";

function lighton(arg){
whichImage = "spec" + arg;
if (jv == "Enabled") document[whichImage].src = "images/odkazy/odkazy_carka.gif";
}
function lightoff(arg){
whichImage = "spec" + arg;
if (jv == "Enabled") document[whichImage].src = "images/pixely/pixel_ciry.gif";
}