$re = '/(\&|\?)(id=\d+)/s';
$str = '//detail.tmall.com/item.htm?abtest=&pvid=42b3a520-35a1-47f8-abe8-572bef4a430f&pos=1&abbucket=&acm=03054.1003.1.2768562&id=604432657613&scm=1007.16862.95220.23864_0_0&utparam=%7B%22x_hestia_source%22%3A%2223864%22%2C%22x_object_type%22%3A%22item%22%2C%22x_mt%22%3A0%2C%22x_src%22%3A%2223864%22%2C%22x_pos%22%3A1%2C%22x_pvid%22%3A%2242b3a520-35a1-47f8-abe8-572bef4a430f%22%2C%22x_object_id%22%3A604432657613%7D';
preg_match($re, $str, $matches, PREG_OFFSET_CAPTURE, 0);
// Print the entire match result
var_dump($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