关于Ajax跨域的问题

Question

XMLHttpRequest cannot load http://study.163.com/webDev/c... Redirect from 'http://study.163.com/webDev/c...' to 'http://study.163.com/systemEr...' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost:8000' is therefore not allowed access.

我只知道这里涉及到了跨域,我用的是绝对地址访问的.浏览器Chrome56.JavaScript高级程序设计上面说是支持XHR原生跨域的.

我想问下这个是服务器端拒绝访问吗?还是地址不对?(这个应该不会)

如果不是,如何访问?

最好是原生JS! 谢谢!