为什么 Chrome 会取消 CORS OPTION 请求

in my app I'm creating AJAX request from HTTP to HTTPS. This means I need CORS. So I add some headers and params to jQuery.ajax and test it. In Firefox everythings works OK, but in Chrome not. Chrome "kill" every preflighed request (OPTIONS).

jQuery 脚本:

$(document).on('click', 'a.ajax', function(e) {
    e.preventDefault();
    $.ajax(this.href, {
        type: 'GET',
        dataType: 'json',
        crossDomain: false,
        headers: {'X-Requested-With': 'XMLHttpRequest'},
        xhrFields: {
            withCredentials: true
        }
    });
    return false;
});

HTTP 转储:

> OPTIONS /foo HTTP/1.1
> User-Agent: curl/7.29.0
> Host: local.bar.cz
> Accept: */*
> Access-Control-Request-Headers:accept, origin, x-requested-with
> Access-Control-Request-Method:GET
> Origin:http://local.bar.cz
> 
< HTTP/1.1 204
< Server: nginx/1.2.7
< Date: Wed, 27 Feb 2013 15:06:54 GMT
< Content-Type: text/html; charset=utf-8
< Connection: keep-alive
< X-Powered-By: Nette Framework
< X-Frame-Options: SAMEORIGIN
< Access-Control-Allow-Origin: http://local.bar.cz
< Access-Control-Allow-Credentials: true
< Access-Control-Allow-Headers: accept, origin, x-requested-with
< Access-Control-Allow-Methods: OPTIONS, GET, POST, HEAD
< 

有人知道为什么 chrome 会终止这个请求吗?