There is no problem in other browsers, but there will be problems in IE8, jump directly to the error of $.ajax, and the readyState returned by alert is 0

$.ajax({ type: "POST", async: false, contentType: "application/x-www-form-urlencoded;charset=UTF-8", xhrFields: { withCredentials: true }, url:url, data:data, success:function (response) { arr = response.Data.ListData; }, error:function (XMLHttpRequest, textStatus, errorThrown) { alert(XMLHttpRequest.readyState); } });

readyState: