public static String md5(String input){
        String valuemd5 = "";
        try{
            RequestBuilder builder = new RequestBuilder(RequestBuilder.GET, "login/md5convert.php?hash="+URL.encodeComponent(input));
            builder.sendRequest("", new RequestCallback(){
                @Override
                public void onError(Request request, Throwable exception){}
                @Override
                public void onResponseReceived(Request request, Response response){
                            String valuemd5 = response.getText();
                            Window.alert(valuemd5);
                            }
            });
        }
        catch (RequestException e){ Window.alert(e.toString());}
    return valuemd5;
    }