$re = '/([^?=&]+)(=([^&]*))?/i';
$str = 'sender=11&receiver=2&subject=3&message=4
sender=AOFJOIA&receiver=p2308u48302rf0&subject=(@#UROJ)(J#OFN:&message=aoefhoa348!!!';
preg_match_all($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