$(function() {
    $("#btnSearch").click(function() {
        var searchkeyword = $("#txtSearch").val();
        if (searchkeyword==""){
            alert("请输入搜索内容！");
             $("#txtSearch").focus();
        }
        else{
            window.location = "search.aspx?q=" + escape(searchkeyword);
        }
       
    });

    $("#txtSearch").keydown(function() {
        if (event.keyCode == 13) { 
           window.event.returnValue = false;
           window.location.href = "search.aspx?q=" + escape($("#txtSearch").val());
          
        }
    })

});