PHP header function usage

What we want to introduce to you today is

// The PHP header function sends a 404 status code to the browser.
Header ("HTTP/1.1 404 Not Found ");
Or
Header ("HTTP/1.1 404 ″);

// PHP header function permanent redirection
Header ("Location: http://weizhifeng.net/"); // The default value is 301.
// Temporary redirection
Header ("HTTP/1.1 302 Found ");
Header ("Location: http://weizhifeng.net /");

// PHP header function download file
Header ("Content-type: text/plain '); // you can replace it with the MIME type you need.
Header ('content-Disposition: attachment; filename=%weizhifeng.txt "');
Readfile('weizhifeng.txt ');

For other header information, refer to HTTP/1.1 specification
If you have output before the PHP header function, use the ob_start () function.