Something causing interference

So I've got the following code that works in jsfiddle, but not on the actual website, which leads me to believe that the only way I'm going to get it working is for someone with more experience than I to look through the source and see what's interfering.

   <script>
        $(document).ready(function(){
    var $elements = $('body').children('div[class^=class]').on('click', function () {
        $elements.removeClass('classname')
                 .not('.' + this.className)
                 .addClass('classname');
    });
    });
    </script>

Website: http://ift.tt/1DF9uGH