如何在Javascript中检测XMLHttpRequest（）的跨源（CORS）网络错误与其他错误

Question

我想检测此错误

XMLHttpRequest cannot load https://accounts.example.com/. No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost' is therefore not allowed access. 

例如：

$.ajax({
  url: "http://api.jquery.com/jquery.ajax/"
}).done(function() {
  alert( "done" );
});