Stuck footer revealed on scroll

stuck-footer.css

#footer {
  position: fixed; bottom: 0; width: 100%;
  z-index:-1;
}

stuck-footer.js

var bumpIt = function() {
      jQuery('body').css('margin-bottom', jQuery('#%%ELEMENT_ID%%').height());
    },
    didResize = false;

bumpIt();

jQuery(window).resize(function() {
  didResize = true;
});
setInterval(function() {
  if(didResize) {
    didResize = false;
    bumpIt();
  }
}, 250);