Find diffidence of two date. By by default this function return in day, But we can get the output in second by third parameter. See below examples:
 
$date = App::Helper('Date')->dateDifference('2013-04-14','1971-12-16'); // Return 15095 Days
pr($date);
 
$date = App::Helper('Date')->dateDifference('2013-04-14','1971-12-16','second'); // Return 1304208000 Second
pr($date);