Is there a way to put php inside of a IE conditional comments
No. You'd probably want to detect the browser in a PHP block as an alternative solution. Something like:
$browser = get_browser();if ($browser->browser == 'MSIE') { if (!is_admin()) { wp_deregister_script('jquery'); wp_register_script('jquery', 'http://ajax.googleapis.com/ajax/libs/jquery/1.5.2/jquery.min.js', false, '1.5.2', true); wp_enqueue_script('jquery'); }}Or using the $is_IE global variable as in Nikolay Yordanov's answer:
if ($is_IE) { if (!is_admin()) { wp_deregister_script('jquery'); wp_register_script('jquery', 'http://ajax.googleapis.com/ajax/libs/jquery/1.5.2/jquery.min.js', false, '1.5.2', true); wp_enqueue_script('jquery'); }}
Short answer: no.
Long answer: IE conditional comments are client side, while PHP is server side, so it won't work.
Possible solution: http://php.net/manual/en/function.get-browser.php (or according to one of the answers already posted, wordpress provides a $is_IE global)