function addEngine(name,ext,cat){
     if ((typeof window.sidebar == "object")
          && (typeof  window.sidebar.addSearchEngine == "function"))
     {
          window.sidebar.addSearchEngine("http://www.zoeklogin.nl/" + name + ".src",
          "http://www.zoeklogin.nl/" + name + "." + ext, name, cat );
     } else {	
          //you could put an error handler here;
	alert("Sorry FireFox only!");
     }
}