// sticky footer plugin
(function($){
  var footer;

  $.fn.extend({
    stickyFooter: function(options) {
      footer = this;
      
      positionFooter();

      $(window)
        .scroll(positionFooter)
        .resize(positionFooter);

      function positionFooter() {
        var docHeight = $(document.body).height() - $("#sticky-footer-push").height();
        if(docHeight < $(window).height()){
          var diff = ($(window).height() - docHeight) -20;
          if (!$("#sticky-footer-push").length > 0) {
            $(footer).append('<div id="sticky-footer-push"></div>');
          }
          $("#sticky-footer-push").height(diff);
        }
      }
    }
  });
})(jQuery);