404:

header ("HTTP/1.1 404 Not Found");301:

header ("HTTP/1.1 301 Moved Permanently"); header ("Location:http://www.baidu.com");下载文件:

header ('Content-type: application/file');header ("Content-Disposition: attachment; filename='test.file'");readfile ("test.file");允许跨域:

header('Access-Control-Allow-Origin:*');设置自定义header头:

header('Access-Control-Allow-Headers:WWW-Authenticate,Authorization,Set-Cookie,X-Requested-With, Accept, Accept-Version, Content-Length, Content-MD5, Content-Type, Date, X-Api-Version,name');