I always assumed that this is the reason why we do this in the first place.
I think the main reason was that old versions of ie go into quirksmode if the doctype is not in the first line of the output e.g.:
<?php header('Content-Type: text/html'); ?> <!DOCTYPE html> -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: http://www.php.net/unsub.php