AjaxPro 行: 错误: “xx”未定义

调试时有错误
 行: 错误: “xx”未定义<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<script type="text/javascript" language="javascript" >
    function display() {
        document.getElementById("浮石").value = xx._Default.ajaxOutput("浮石").value;
        document.getElementById("浮石").style.visibility = "visible";
    }
</script>
<title>示例</title></head>
<body onload="display()">namespace xx
{
    public partial class _Default : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            AjaxPro.Utility.RegisterTypeForAjax(typeof(xx._Default));
        }
        public string outputdata(string str1)
        {
           //略
        }
        [AjaxPro.AjaxMethod]
        public string ajaxOutput(string str)
        {
            return outputdata(str);
        }
    }
}<system.web>
    <httpHandlers>
      <add verb="*" path="*.ashx" type="AjaxPro.AjaxHandlerFactory,AjaxPro.2"/>
    </httpHandlers>
    <compilation debug="true" targetFramework="4.0">
      <assemblies>
请问如何解决？谢谢！