Set Distance From Bottom, Stop Fixed Position

fromBottom.js

// Adjust location of 'back to top' near the bottom of the page
function notTooNearTheBottom() {
    var viewportHeight = $(window).height();
    var actionsArea = $(window).scrollTop() + viewportHeight;
    var bottomBoundary = $(document).height() - 90; // this is our 'safe area'
    
    if( actionsArea > bottomBoundary ) {
        // console.log('near the bottom - move 'up to top', hide 'comments');
        $('#action-top').css('top', bottomBoundary);
    }
    else {
       $('#action-top').css('top',''); //clear the inline css 
    }
}

// watch the scroll event
$(window).scroll(function(){
    
    //but - don't watch it too much. let's clear the timeout
    clearTimeout(window.scroll_timeout); //.scroll_timeout is the variable
    
    window.scroll_timeout = setTimeout(function() { 
        // function to call
        notTooNearTheBottom();
    }, 20);  // wait 'this long' to fire

});

fromBottom.scss

#go-to-the-top {
  top: 88%; // alternative to js - keeping it near the bottom
  transition: top 250ms; // animate the transition
  a:hover:after, a:active:after { // add nice label on hover
    content: '\A top';
    font-size: 1.5rem;
    white-space: pre;
    vertical-align: top;
  }
}

the-bottom-line.md

from the Bottom

Started from the bottom, now we're here.

This little bit of js and css makes it so that the 'back to the top' link will only go so far down on the page. It was born out of not wating the link to lay over the footer section.