javascript - 关于浏览器跨域cookie的问题

Question

我先描述我遇到的情况：

nodejs后端，设置：

app.all('*', function(req, res, next) {
  console.log("appuse");
  res.header("Access-Control-Allow-Origin","*");
  res.header("Access-Control-Allow-Headers","Origin, Accept-Language, Accept-Encoding,X-Forwarded-For, Connection, Accept, User-Agent, Host, Referer, Cookie, Content-Type, Cache-Control,*");
  res.header("Access-Control-Allow-Methods","PUT,POST,GET,DELETE,OPTIONS");
  res.header("Access-Control-Allow-Credentials",true);
  res.header("X-Powered-By",' 3.2.1');
  res.header("Content-Type", "application/json;charset=utf-8");
  next();
});

然后前端ajax请求后端，后端会返回set-cookie

set-cookie:connect.sid=s%3ACOrynUfg9BleXlivy2GWX2n6gYzSnHoP.lX51TZD1YazMhcDJFTdqwPjN6pL7q1dcAhCEElVRGxQ; Path=/; Expires=Sun, 30 Oct 2016 16:15:03 GMT; HttpOnly

像上面那样

Answer 1

服务器如果要发送Cookie，Access-Control-Allow-Origin就不能设为星号，必须指定明确的、与请求网页一致的域名。同时，Cookie依然遵循同源政策，只有用服务器域名设置的Cookie才会上传，其他域名的Cookie并不会上传，且（跨源）原网页代码中的document.cookie也无法读取服务器域名下的Cookie。

Answer 2

在使用ajax时需要withCredentials参数为true浏览器在跨域时才会带上cookie

var xhr = new XMLHttpRequest();
xhr.open('GET', 'http://example.com/', true);
xhr.withCredentials = true;
xhr.send(null);

http://devdocs.io/dom/xmlhttp...

$.ajax({
   url: a_cross_domain_url,
   xhrFields: {
      withCredentials: true
   }
});

http://devdocs.io/jquery/jque...