Jquery for Setting Fixed Up Html Block on page Scrolling

jQuery(function(){
 if (jQuery(".woodocs-toc").length > 0) {

  var top = jQuery('.woodocs-toc').offset().top - 140 - parseFloat(jQuery('.woodocs-toc').css('marginTop').replace(/auto/, 0));
  var toc_height = jQuery('.woodocs-toc').height();

  jQuery(window).scroll(function (event) {
   // what the y position of the scroll is
   var y = jQuery(this).scrollTop();
   var window_height = jQuery(window).height();
   var footer_top = jQuery('#footer').offset().top;

   if ( ( y + toc_height + 140 ) <= ( footer_top ) ) {
    jQuery('.woodocs-toc').fadeIn();
   } else {
    jQuery('.woodocs-toc').fadeOut();
   }

   if ( y >= top && toc_height < ( window_height - 140 ) ) {
    // if so, ad the fixed class
    jQuery('.woodocs-toc').addClass('fixed-toc');
   } else {
    // otherwise remove it
    jQuery('.woodocs-toc').removeClass('fixed-toc');
   }
  });
 }
});