Assign the callback uppon initialization, format the countdown %w weeks %d days %H hours %M minutes %S seconds where each directive value is displayed within his own DOM element (<span>) and all are zero-padded.
New year's eve in
HTML:
<div id="clock"></div>JS:
$('#clock').countdown('2020/10/10', function(event) {
var $this = $(this).html(event.strftime(''
+ '<span>%w</span> weeks '
+ '<span>%d</span> days '
+ '<span>%H</span> hr '
+ '<span>%M</span> min '
+ '<span>%S</span> sec'));
});