function showhide(rownum) {
   if(document.getElementById) {
      var rownumid = document.getElementById(rownum).style;

      //Set the object to table-cell if the browser is
      //Firefox and block if it's anything else.
      if(navigator.userAgent.indexOf("Firefox") != -1){
         if(rownumid.display == "block") {
            rownumid.display = "none";
         }
         else {
            rownumid.display = "block";
         }
      }
      else {
         if(rownumid.display == "block") {
            rownumid.display = "none";
         }
         else {
            rownumid.display = "block";
         }
      }
      return false;
   }
   else {
      return true;
   }
}