指定标头时，jQuery AJAX 无法工作（发出 OPTIONS 飞行前请求）
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jQuery AJAX fails to work (OPTIONS pre-flight request made) when headers are specified
提问by Deepak Thomas
The AJAX request works fine, but the moment I add a header via beforeSend or headers, an OPTIONS pre-flight request is made and the GET request is aborted.
AJAX 请求工作正常，但是当我通过 beforeSend 或 headers 添加标头时，会发出一个 OPTIONS 飞行前请求并中止 GET 请求。
Code: $.ajax({
type: "GET",
crossDomain: true,
beforeSend: function (xhr)
{
xhr.setRequestHeader("session", $auth);
},
url: $url,
success: function (data) {
$('#something').html(data);
},
error: function (request, error) {
$('#something').html("<p>Error getting values</p>");
}
});
SimilarAJAX Request w/o headers specified (the moment I add/modify header, an OPTIONS call is made)
没有指定标头的类似AJAX 请求（在我添加/修改标头的那一刻，进行了 OPTIONS 调用）
Request GET /api/something?filter=1 HTTP/1.1
Referer http://app.xyz.dj/dashboard
Accept application/json, text/javascript, */*; q=0.01
Accept-Language en-US
Origin http://app.xyz.dj
Accept-Encoding gzip, deflate
User-Agent Mozilla/5.0 (Windows NT 6.3; WOW64; Trident/7.0; MASMJS; rv:11.0) like Gecko
Host 162.243.13.172:8080
DNT 1
Connection Keep-Alive
Cache-Control no-cache
Similar Server Response Header (for GET request)
类似的服务器响应头（用于 GET 请求）
Response HTTP/1.1 200 OK
Server Apache-Coyote/1.1
Access-Control-Allow-Origin *
Access-Control-Allow-Methods GET, POST, DELETE, PUT, OPTIONS, HEAD
Access-Control-Allow-Headers Content-Type, Accept, X-Requested-With
Access-Control-Allow-Credentials true
Content-Type application/json
Transfer-Encoding chunked
Date Thu, 09 Jan 2014 14:43:07 GMT
What I am doing wrong?
我做错了什么？
采纳答案by Deepak Thomas
Solved. Thanks @JasonP for pointers. Changed Server Response Headersfrom
解决了。感谢@JasonP 的指点。更改了服务器响应头从
Access-Control-Allow-Headers:*
访问控制允许标题：*
to specific ones
到特定的
Access-Control-Allow-Headers: Content-Type, Accept, X-Requested-With, Session
Access-Control-Allow-Headers: Content-Type, Accept, X-Requested-With, Session
and now it works!
现在它起作用了！
