nginx 图片，js，css等文件允许跨域

location ~ .*\.(gif|jpg|jpeg|png|bmp|swf|flv|mp4|ico)$ {
   #允许跨域请求
    add_header Access-Control-Allow-Origin '*';
    add_header Access-Control-Allow-Headers X-Requested-With;
    add_header Access-Control-Allow-Methods GET,POST,OPTIONS;

    expires 30d;
    access_log off;
  }