function errorMsg() {
   alert("Netscape 6 or Mozilla is needed to install a search plugin.");
}

function addEngine(name,ext,cat,type) {
   if ((typeof window.sidebar == "object") && (typeof window.sidebar.addSearchEngine == "function")) {
      window.sidebar.addSearchEngine(
      "http://mycroft.mozdev.org/install.php/" + type + "/" + name + ".src",
      "http://mycroft.mozdev.org/install.php/" + type + "/" + name + "."+ ext, name, cat );
   }
   else {
      errorMsg();
   }
}