<!-- if (ns3up || ie4up) -->

browserName = navigator.appName;
browserVer = parseInt(navigator.appVersion);

ns3up = (browserName == "Netscape" && browserVer >= 3);
ie4up = (browserName.indexOf("Microsoft") >= 0 && browserVer >= 4);
op6up = (browserName == "Opera" && browserVer >= 6);

 function zmenobr(urlObrazku) {
 if (ns3up)
 {
 imgOn = (urlObrazku);
 document.obr1.src = imgOn;
 }
 else
 {
 imgOn = (urlObrazku);
 obr1.src = imgOn;
 }
 }

 function zvetsiobr(urlObrazku) {
 if (ns3up)
 {
 imgOn = (urlObrazku);
 document.obr2.src = imgOn;
 }
 else
 {
 imgOn = (urlObrazku);
 obr2.src = imgOn;
 }
 }
 
  function zhodobr(urlObrazku) {
 if (ns3up)
 {
 imgOff = (urlObrazku);
 document.obr2.src = imgOff;
 }
 else
 {
 imgOff = (urlObrazku);
 obr2.src = imgOff;
 }
 }