function Go_Search() {
        var searchText = $("#textfield").val();
        
        var aa = encodeURI(searchText);

        if ((searchText == "请输入您要搜索的关键词" || searchText == "")) {

        $("#ahref").attr("href", "/default.shtml");

        } 
        else {

            
            window.location="/Search.aspx?keyword="+aa;
        }
    }
  
  if (document.addEventListener) {//如果是Firefox
        document.addEventListener("keypress", fireFoxHandler, true);
        }
        else {
        document.attachEvent("onkeypress", ieHandler);
        }

        function fireFoxHandler(evt){                
        if (evt.keyCode == 13) {
        Go_Search();
        return false;
        }
        }

        function ieHandler(evt){               
        if (evt.keyCode == 13) {
        Go_Search();
        return false;
        }
    }