Hours Mins and Seconds difference between two dates.

// Hours Mins and Seconds difference between two dates.
function timeDifference($date1=null, $date2=null)
{
 $date1 = !empty($date1) ? $date1 : date('Y-m-d H:i:s');
 $date2 = !empty($date2) ? $date2 : date('Y-m-d H:i:s');
 
 $dateDiff    = abs(strtotime($date1) - strtotime($date2));
 
    $fullHours   = floor($dateDiff / (60*60) );
    $fullMinutes = floor(($dateDiff-($fullHours*60*60))/60);   
    $fullSeconds = ($dateDiff-($fullHours*60*60)-($fullMinutes*60));
    
    return ('T-'.$fullHours.':'.$fullMinutes.':'.$fullSeconds);
}