function installSearchEngine() {
 if (window.external && ("AddSearchProvider" in window.external)) {
   // Firefox 2 and IE 7, OpenSearch
   window.external.AddSearchProvider("http://wikipedia.fredmus.com/xml/zeekersearch.xml");    
 } else {
   // No search engine support (IE 6, Opera, etc).
   alert("The search plugin is only available for IE7 or Firefox 2 (or higher)");
 }
}