先后台交互方法

前台用ajax :

var result = false;
                    $.ajax({
                        type: "Post",
                        url: "KYGL_QT_Search.ashx",
                        data: "flowsn="+flowsn,
                        async: false,
                        error: function () {
                            alert('链接超时');
                        },
                        success: function (data) {//data为本身定义的返回值
                            if (data == "true") {
                                alert('该矿已经抵押3次');
                            }
                            else {
                                result = true;
                            }
                        }
                    });

创建 ashx  交互文件：

public void ProcessRequest(HttpContext context)
        {
            string flowsn = context.Request["flowsn"];
            string result = "false";
            string sql = "";
            int count =Convert.ToInt32( DbFactory.Instance.GetDbHelp().ExecuteScalar(sql));
            if (count >= 3) {
                result = "true";
            }
            context.Response.ContentType = "text/plain";
            context.Response.Write(result);
        }