date time difference function in PHP

function dateDiff($dt1, $dt2, $timeZone = 'GMT')
{
  $tZone = new DateTimeZone($timeZone);
  $dt1 = new DateTime($dt1, $tZone);
  $dt2 = new DateTime($dt2, $tZone);

  $ts1 = $dt1->format('Y-m-d');
  $ts2 = $dt2->format('Y-m-d');

  $diff = abs(strtotime($ts1)-strtotime($ts2));

  $diff/= 3600*24;
  //$diff/=60   if you want to check minutes difference


  return $diff;
}