bName = navigator.appName;
  bVer = parseInt(navigator.appVersion);
  if ((bName == "Netscape" && bVer < 3) ||
     (bName == "Microsoft Internet Explorer" && bVer < 4)) br = "n2";
  else br = "n3";


 function TimgDo(imgName)
 {
   if (br == "n3")
   {
     document[imgName].src = "/m/"+imgName + "_on.gif";
     document["is_text"].src = "/m/"+imgName + "_is.gif";
   }
 }
 function TimgUnDo(imgName)
 {
   if (br == "n3")
   {
     document[imgName].src = "/m/"+imgName + "_no.gif";
         }
 }

function VimgDo(imgName)
 {
   if (br == "n3")
   {
     document[imgName].src = "/m/"+imgName + "_b.gif";
   }
 }
 function VimgUnDo(imgName)
 {
   if (br == "n3")
   {
     document[imgName].src = "/m/"+imgName + "_a.gif";
   }
 }