非常实用的header()函数实用介绍：
/**php中header函数用法实例总结: 希望对你有帮助！*/
//1. 页面没找到 Not Found
header(‘HTTP/1.1 404 Not Found’);
//2. 用这个header指令来解决URL重写产生的404 header
header(‘HTTP/1.1 200 OK’);
//3. 访问受限
header(‘HTTP/1.1 403 Forbidden’);
// The page moved permanently should be used for
// all redrictions, because search engines know
// what’s going on and can easily update their urls.
//4. 页面被永久删除，可以告诉搜索引擎更新它们的urls
header(‘HTTP/1.1 301 Moved Permanently’);
//5. 服务器错误
header(‘HTTP/1.1 500 Internal Server Error’);
//6. 重定向到一个新的位置
header(‘Location: http://www.example.org/’);
//7. 延迟一段时间后重定向
header(‘Refresh: 10; url= http://www.example.org/’);
echo ’You will be redirected in 10 seconds’;
//8. 加载要下载的文件:
readfile(‘example.zip’);
//9. 也可以使用HTML语法来实现延迟
header(‘Content-Transfer-Encoding: binary’);
//10. 禁止缓存当前文档:
header(‘Cache-Control: no-cache, no-store, max-age=0, must-revalidate’);
header(‘Expires: Mon, 26 Jul 2010 05:00:00 GMT’);
header(‘Pragma: no-cache’);
//11. 显示登录对话框，可以用来进行HTTP认证
header(‘HTTP/1.1 401 Unauthorized’);
header(‘WWW-Authenticate: Basic realm=“Top Secret”‘);
echo ’Text that will be displayed if the user hits cancel or ’;
echo ’enters wrong login data’;
//12. 设置内容类型:
header(‘Content-Type: text/html; charset=iso-8859-1′);
header(‘Content-Type: text/html; charset=utf-8′);
header(‘Content-Type: text/plain’); // plain text file
header(‘Content-Type: image/jpeg’); // JPG picture
header(‘Content-Type: application/zip’); // ZIP file
header(‘Content-Type: application/pdf’); // PDF file
header(‘Content-Type: audio/mpeg’); // Audio MPEG (MP3,…) file
header(‘Content-Type: application/x-shockwave-flash’); // Flash animation