PHP function to get age for date of birth

 PHP function to get age for date of birth  

function age_from_dob($dob){

$dob = strtotime($dob);
$y = date('Y', $dob);
 if (($m = (date('m') - date('m', $dob))) < 0) {
  $y++;
 } elseif ($m == 0 && date('d') - date('d', $dob) < 0) {
  $y++;
 }
return date('Y') - $y;

 } 

 echo age_from_dob('2005/04/19'); date in yyyy/mm/dd format.