优化ajax提交数据的用户体验

$.ajax({            type : 'put',            url  : '',            data : loaddata,            async : false,            dataType: 'json',            contentType: "application/json;charset=utf-8",            beforeSend: function () {                // 禁用按钮防止重复提交                $("#submit").attr({ disabled: "disabled" });                $("loading").show();            },            success: function (data) {            },            complete: function () {                $("#submit").removeAttr("disabled");                $("loading").hide();            },            error: function (data) {                console.info("error: " + data.responseText);            }        });