Question

I am trying to get the ID from transaction(123456) in the HTML

It doesn’t seem to return anything.

 $response = "</body> </html><script type='text/javascript'>transaction(123456);</script>";

 preg_match('/^transaction\((\d+)\)/', $response, $match);

 print_r($match);

if (is_numeric($match[1])) {
  echo "Your ID: " . $match[1];
}

Answer 1

Because you have the start of string anchor ^, and transaction( isn’t at the start of the string. Remove that (or add a non-greedy match) and it’ll work (as shown by this demo):

preg_match('/transaction\((\d+)\)/', $response, $match);