function addEngine(name,ext,cat,type)
    {
      if ((typeof window.sidebar == "object") && (typeof window.sidebar.addSearchEngine == "function")) {
        window.sidebar.addSearchEngine(
          "http://mycroft.mozdev.org/external.php/" + name + ".src",
          "http://mycroft.mozdev.org/external.php/" + name + "."+ ext, name, cat );
      } else {
        alert("You will need a Mozilla based browser to install a search plugin.");
      }
    }