Wilfred · May 7, 2009 21:21
diff --git a/header.php b/header.php
 <?php
 //based on http://lists.w3.org/Archives/Public/www-validator/2007Jul/0208.html
 $mime = 'text/html'; //fallback
 // set xhtml mimetype if browser claims it accepts it:
 if(!empty($_SERVER['HTTP_ACCEPT']) && stristr($_SERVER['HTTP_ACCEPT'],'application/xhtml+xml')) {
 	$mime = 'application/xhtml+xml';
 }
 // or if it is the validator:
 if (stristr($_SERVER["HTTP_USER_AGENT"],"W3C_Validator") OR stristr($_SERVER["HTTP_USER_AGENT"],"W3C_CSS_Validator") OR
 stristr($_SERVER["HTTP_USER_AGENT"],"WDG_Validator")) {
    $mime = "application/xhtml+xml";
 }
 // and put into http header:
 header('Content-Type: '.$mime.';charset=utf-8');
 // xml prolog:
 echo("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n");
 // only add doctype if we are serving xhtml -- want to trigger quirks mode otherwise
 // unnecessary?
 if ($mime == 'application/xhtml+xml') {
 	echo ('<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN"
   "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">');
 }
 ?>