//页面调用
 function GetBgPicInfo() {
        categoryid = $(".categorybuttonhover").attr("id"); //类别id
        sort = $(".categorybuttonhover").attr("sort");
        pagenum = $("#pagenumtexttwo").val();
        $.get('bgpic.aspx/bgpics', { categoryid: categoryid, sort: sort, pagenum: pagenum }, function (result) {
            $("#bgpicsinfo").html(result);
        });
    };

using System.Web.Services;

//服务端 这个方法的页面叫bgpic.aspx
  [WebMethod(Description = "获取指定的图片缩略图")]
        public string bgpics(string ids, string sort, int pagenum = 1)
        {
            return "服务端信息";
}