JQUERY AJAX
 $.ajax({
          type:"POST",
          url:"Handler/BackHandler.ashx",
          data:"cmd=ShowUserInfo&sStr="+vStr,
          beforeSend:function()
          {
              
          },
          error:function(da)
          {
          
            },
          success:function(data)
          {
 
          }
          });

WEBCONFIG
<httpHandlers>
          <add verb="POST,GET" path="ajax/*.ashx" type="Ajax.PageHandlerFactory, Ajax"/>
        </httpHandlers>

当前页加入
 protected void Page_Load(object sender, EventArgs e)
    {
Ajax.Utility.RegisterTypeForAjax(typeof(Default));
}
[Ajax.AjaxMethod()]
    public string  ShowAjax(string vName)
    {
   return "welcome"+vName;
}

Code
<script language=javascript >
function ShowAjax()
{
Default.ShowAjax("woody",CallBack);

}
function CallBack(response)
{
  alert(response.value);
}
</script>