Question

How to make a back-to-top link slide up to position X (footer top) when the bottom of the browser window is reached i.e. when the user has completely scrolled down the page?

Right now, my page has a functioning back-to-top link that is fixed to the window bottom. However, there’s a footer at the end of the page and the back-to-top link needs to stay (or snap back) on top of the footer at the end of the page and not the browser window’s bottom.

Toplink’s script is:

//plugin
jQuery.fn.topLink = function(settings) {
  settings = jQuery.extend({
    min: 1,
    fadeSpeed: 200
  }, settings);
  return this.each(function() {
    //listen for scroll
    var el = $(this);
    el.hide(); //in case the user forgot
    $(window).scroll(function() {
      if($(window).scrollTop() >= settings.min)
      {
        el.fadeIn(settings.fadeSpeed);
      }
      else
      {
        el.fadeOut(settings.fadeSpeed);
      }
    });
  });
};

//usage w/ smoothscroll
$(document).ready(function() {
  //set the link
  $('#top-link').topLink({
    min: 400,
    fadeSpeed: 500

  });
  //smoothscroll
  $('#top-link').click(function(e) {
    e.preventDefault();
    $.scrollTo(0,500);
  });
});

Answer 1

You can just check if the user scrolled down to bottom page like this:

$(window).scroll(function() {           
   if($(window).scrollTop() + $(window).height() == $(document).height()) {
      console.log("bottom reached");
   }            
});

If the bottom is reached, you could set the position of your link as you like it or animate it to jump a little up or something like that.