我的json请求不会触发beforeSend请求。似乎无法找出原因

Question

Notes

1. This is jQuery 1.4.4
2. This is not a jsonp request. Just vanilla json within my domain.

My Request

$autocomplete_xhr = $.ajax({
  url: '/customers/filter.json',
  contentType: "application/json",
  data: { name: request.term },
  dataType: 'json',
  beforeSend: function(xhr) {
   console.log('Inside beforeSend');
   console.log(xhr);
  },

When I send the AJAX request out, console.log will not fire off.

What do you think the problem is?

Answer 1

clearly said in docs

beforeSend(jqXHR, settings)

A pre-request callback function that can be used to modify the jqXHR (in jQuery 1.4.x , XMLHTTPRequest) object before it is sent. Use this to set custom headers, etc. The jqXHR and settings maps are passed as arguments. This is an Ajax Event. Returning false in the beforeSend function will cancel the request. As of jQuery 1.5, the beforeSend option will be called regardless of the type of request.