$re = '/(\w+)\/(\w+)(?:\+(\w+))?(?:\s?;\s?([\w-]+)=([\w!:\$\.-]+))?(?:\s?;\s?((?4))=((?5)))?(?:\s?;\s?((?4))=((?5)))?(?:\s?;\s?((?4))=((?5)))?(?:\s?;\s?((?4))=((?5)))?(?:\s?;\s?((?4))=((?5)))?(?:\s?;\s?((?4))=((?5)))?(?:\s?;\s?((?4))=((?5)))?/';
$str = 'application/xhtml+xml; q=0.9; level=3 , text/html,application/json;test=hello
application/xhtml+json; q=1000; level=4 ; w=40';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php