How do i run a php script every second?

Question

I am currently writing a online game. Now I have to check if an event happen (checking timestamp in database) and depending on that execute some actions. I have to check for

Answer 1

$total_time = 0;
$start_time = microtime(true);
while($total_time < 60)
  {
        //DoSomethingHere;
    echo $total_time."\n";
    //sleep(5);
  $total_time =  microtime(true) - $start_time ;
  } 

add this in crontab to run every minute.