function isScrolledIntoView(elem) {
  if (elem.length) {
	var docViewTop = $(window).scrollTop();
	var docViewBottom = docViewTop + $(window).height();
        var elemTop = $(elem).offset().top - 300;
	var elemBottom = elemTop + $(elem).height();

	return ((elemBottom <= docViewBottom) && (elemTop >= docViewTop));
   }
}

if (isScrolledIntoView($('.site-footer'))) {
   $('body').addClass('footer-visible');
} else {				 
   $('body').removeClass('footer-visible');
}