ajax异步提交修改按钮文字

function btnParsingOnClick() {
            $.ajax({
                type: "GET",
                url: url + "?action=startparsing&r=" + Math.random(),
                dataType: "json",
                data: null,
                async: true,
                beforeSend: function () {
                    //$("#btnStartParsing").prop("value", "Processing, please wait...,Do not click again or close page");
                    $("#btnStartParsing").val("Processing, please wait...,Do not refresh or close page");
                    $("#btnStartParsing").prop("disabled", true);
                },
                success: function (json) {

                    $("#parsingResult").text(json.msg);

                    loadShareFolderXml();
                },
                complete: function () {
                    $("#btnStartParsing").val("Start Parsing");
                    loadShareFolderXml();
                },
                error: function (XMLHttpRequest, textStatus, errorThrown) { alert(textStatus); }
            });

            return false;
        }