防止ajax重复提交

var $Common = {
request: {      //请求
        ajaxTimeFn: {
            time: null,
            url: null,
            data: null
        }, //防止重复提交 延迟
        ajax: function (url, data, callback, async) {
            /// <summary>
            /// ajax 请求
            /// </summary>
            /// <param name="url">服务器地址</param>
            /// <param name="data">请求参数</param>
            /// <param name="callback">回调函数</param>
            /// <param name="async">是否同步 默认:false关闭异步 true或不设置 均为开启异步</param>
            /// <param name="isLoading">是否运行Loading...(运行loading会出现无法同步运行问题)</param>

            //防止多次提交
            if ($Common.request.ajaxTimeFn.url == url && $Common.request.ajaxTimeFn.data == data) {
                $Common.request.ajaxTimeFn.time = setTimeout(function () {
                    action(function () {
                        clearTimeout($Common.request.ajaxTimeFn.time);
                        $Common.request.ajaxTimeFn.time = null;
                    });
                }, 400);                
            } else {
                action(function () {
                    clearTimeout($Common.request.ajaxTimeFn.time);
                    $Common.request.ajaxTimeFn.time = null;
                });
            }
            $Common.request.ajaxTimeFn.url = url;
            $Common.request.ajaxTimeFn.data = data;

            function action(callback2) {
                /// <summary>
                /// 执行
                /// </summary>
                $.ajax({
                    url: url,
                    data: data,
                    type: ‘POST‘,
                    async: !async ? false : true,      //是否同步 false:同步 true:异步                    
                    contentType: "application/x-www-form-urlencoded",
                    dataType: "json",
                    success: function (result, textStatus) {
                        if ($.isFunction(callback)) {
                            var json;
                            try { json = JSON.parse(result); } catch (ex) { json = result; }
                            callback(json);
                        }

                        //防止多次提交
                        if ($.isFunction(callback2)) callback2();

                    }, error: function (msg) {
                        var n = "";
                        //防止多次提交
                        if ($.isFunction(callback2)) callback2();

                    }
                });
            }
        }
    }
}