function showSelect(isOn)
{
   if(document.layers) // it's Netscape 4.x
   {
      document.layers["navform"].visibility = isOn ? "show" : "hide";
	 }
	 else if(document.getElementById) // it's Mozilla, Netscape 6 or IE 6
	 {
	 		document.getElementById("navform").style.visibility = isOn ? "visible" : "hidden";
	 }
	 else if(document.all) //it's IE 4 or 5 
	 {
      document.all("navform").style.visibility = isOn ? "visible" : "hidden";
   }
   else //it's some other browser
	 {
     document.navform.visibility = isOn ? "show" : "hide";
   }
}