function installSearchPlugin(spu) {
    try {
      window.external.AddSearchProvider(spu);
    }
    catch(e) {
      alert("Die Installation hat nicht geklappt:  "+ e);
    } // catch
    return undefined;
  } // _installSearchPlugin
  
var add_ok = ('object' == typeof(window.external)) && ('undefined' != typeof(window.external.AddSearchProvider));