detect php max timeout limit on shared hosting

timeout_detect.php

<?php
$max_timeout = 600;

$start = time();
   
register_shutdown_function('shutdown',$start);
   
for(;;) 
{
$finish = time();
$total = $finish - $start;
       
  if($total >= $max_timeout) 
  {
   exit;
  }
 	
 }
	
function shutdown($start)
{
 $finish = time();
 $total = $finish - $start;
 // Store $total in DB
  echo json_encode($total);
}
	
?>