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