jQuery：同位素，按日期排序

I'm having some trouble sorting isotope elements by dates, the elements being wordpress posts, thus the date getting pulled in by php.
HTML / PHP:

<div id="blog-grid">

<div class="blog-grid date" data-time="<?php the_time('Y-m-d H:i:s') ?>">
</div>

<div class="blog-grid-text date" data-time="<?php the_time('Y-m-d H:i:s') ?>">
</div>

</div>

jQuery:

$(window).load(function(){

var $container = $('#blog-grid');

$container.imagesLoaded( function(){
$container.isotope({
    itemSelector: '.blog-grid, .blog-grid-text',
sortBy: {
    time: function( $elem ) {
      return $elem.find('.date').attr('data-time');
    }
  },
    animationEngine: 'best-available',
    masonry: {
    columnWidth: 3,
    gutterWidth: 20
    }
});
    });

  });

This doesn't seem to work, I can't find a solution that does. The date can be in any format if that helps, but I'm not exactly sure how to then sort these posts by date (descending). Any suggestions would be greatly appreciated!

Format your dates to Unix Timestamp first. That way you sort by a integer value. Pass your time-string to strtotime() to convert it easily.

Then I don't really temember, but I think you need to set the default sorting as well. Set that to time in that case.