$pat_a = array (
'/.+(\\&'.$var.')=(.*)\\&/AU', /* in the middle */
'/.+\\?('.$var.')=(.*\\&).+/AU', /* at front, more follow */
$pat_a = array (
'/.+(\\&'.$var.')=(.*)\\&/AU', /* in the middle */
'/.+\\?('.$var.')=(.*\\&).+/AU', /* at front, more follow */