ajax更新的时候正在更新数据的弹框,更新完后再弹出成功的提示,debugger;const form = new FormData();form.append("serviceName", "syncWmsBarCode2OdsService");const settings = { "async": true, "crossDomain": true, "url": "http://100.110.100.112:80/api", "method": "POST", "headers": {}, "processData": false, "contentType": false, "mimeType": "multipart/form-data", "beforeSend": function () { $("#msg").text("正在更新数据...."); return true; }, "data": form };$.ajax(settings).done(function (response) { console.log(response); alert(response+"数据更新完成,请进行查询操作");});现在的问题是beforeSend这个方法没提示。