Кнопки вверх/низ

vertical_navigation.css

.wrap-bottom {
  position: fixed;
  right: 15px;
  bottom: 25px;
}
#ToTop,
#OnBottom {
  width: 36px;
}
.go-up {
  position: relative;
  z-index: 9999;
  cursor: pointer;
  font-size: 40px;
  opacity: .6;
  display: block;
}
.go-up .fa-chevron-circle-up {
  color: #AD9B74;
}
.go-down .fa-chevron-circle-down {
  color: #AD9B74;
}
.go-down {
  bottom: 10px;
}
.go-down:hover,
.go-up:hover {
  opacity: 1;
}

vertical_navigation.html

<div class="wrap-bottom">
    <div class="go-up" title="Top" id="ToTop" style="left: 0px;"><i class="fa fa-chevron-circle-up"></i></div>
    <div class="go-down" title="Bottom" id="OnBottom" style="left: 100px;"><i class="fa fa-chevron-circle-down"></i></div>
</div>

vertical_navigation.js

jQuery(function(){
    var trigerTop = 'show';
    var trigerBottom = 'show';
    var noSckroll = false;
        hideButtonTop();

    function hideButtonTop(){
        if(trigerTop == 'show'){
            jQuery("#ToTop").animate({ "left": "+=100px" }, "slow" );
            trigerTop = 'hide';
        }
    }
    function showButtonTop(){
        if(trigerTop == 'hide'){
            jQuery("#ToTop").animate({ "left": "-=100px" }, "slow" );
            trigerTop = 'show';
        }
    }
    function hideButtonBottom(){
        if(trigerBottom == 'show'){
            jQuery("#OnBottom").animate({ "left": "+=100px" }, "slow" );
            trigerBottom = 'hide';
        }
    }
    function showButtonBottom(){
        if(trigerBottom == 'hide'){
            jQuery("#OnBottom").animate({ "left": "-=100px" }, "slow" );
            trigerBottom = 'show';
        }
    }

    jQuery(window).scroll(function(){
    if (jQuery(window).scrollTop()<="250") {
        if(!noSckroll)
            hideButtonTop();
    }else {
        if(!noSckroll)
            showButtonTop();
    }

    });
    jQuery(window).scroll(function(){
        if (jQuery(window).scrollTop()>=jQuery(document).height()-"999"){
            if(!noSckroll)
                hideButtonBottom();
        }
        else {
            if(!noSckroll)
                showButtonBottom();
        }
    });

    jQuery("#ToTop").click(function(){
        noSckroll = true;
        jQuery("html,body").animate({scrollTop:0},"slow",function(){noSckroll = false;})
            hideButtonTop();
            showButtonBottom();
    });

    jQuery("#OnBottom").click(function(){
        noSckroll = true;
        jQuery("html,body").animate({scrollTop:jQuery(document).height()},"slow",function(){noSckroll = false;})
            showButtonTop();
            hideButtonBottom();
    });
});