JSFiddle - React, Tailwind, and code Playground

by Gaius Martius

HTML

<!--СКРОЛЛ ВВЕРХ-->
		<div class="scroll_up">Up</div>
<!-- СКРОЛЛ ВНИЗ -->
		<div class="scroll_down">Down</div>
<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.</p>
<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.</p>
<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.</p><p>Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.</p>
<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do...

CSS

/*---СКРОЛЛЫ ---*/
.scroll_up,
.scroll_down {
	position: fixed;
	z-index: 100;
  padding: 6px 3px 0;
	width: 45px;
	height: 25px;
	border: 1px solid #fff;
  border-radius: 5px;
	text-align: center;
	background-color: rgba(251, 131, 114,.5);
	color: #fff;
  cursor: pointer;
  -webkit-transition: text-shadow,background-color .3s ease-in-out;
	-moz-transition: text-shadow,background-color .3s ease-in-out;
	-o-transition: text-shadow,background-color .3s ease-in-out;
	transition: text-shadow,background-color .3s ease-in-out;
}

.scroll_up {
  display: none;
	bottom: 50px;
	right: 5px;
}
.scroll_down {
  display: block;
	bottom: 10px;
	right: 5px;
}

.scroll_up:hover, .scroll_down:hover {
	text-shadow: 0px 1px 4px #ccc;
	background-color: #ff3f25;
	-webkit-transition: text-shadow,background-color .3s ease-in-out;
	-moz-transition: text-shadow,background-color .3s ease-in-out;
	-o-transition: text-shadow,background-color .3s ease-in-out;
	transition: text-shadow,background-color .3s ease-in-out;
}

JavaScript

var _window = $(window),
		_html_body = $('html, body'),
    _body = $('body'),
		_scroll_up = $('.scroll_up'),
		_scroll_down = $('.scroll_down');

//	ПОЯВЛЕНИЕ КНОПОК-СКРОЛЛИНГА
  _window.scroll(function(){
    var that = $(this);
    if ( that.scrollTop() > 20 ){
        _scroll_up.fadeIn(400);
    } else {
        _scroll_up.fadeOut(400);
    };
    
//	ДЖЕДАЙСКАЯ ПРОВЕРКА ТОГО, ЧТО ДОКРУТИЛИ ДО КОНЦА ДОКУМЕНТА
    if ( $(document).height() <= (that.height() + that.scrollTop()) ){
        _scroll_down.fadeOut(400);
    } else {
				_scroll_down.fadeIn(400);
		}
   
  });// END OF _window.scroll(...)

//	ПЛАВНАЯ ПРОКРУТКА НА 10% ВВЕРХ
  _scroll_up.click(function(){
    _html_body.animate({
        scrollTop: _window.scrollTop() - _body.height() / 10
    }, 600);
  });

//	ПЛАВНАЯ ПРОКРУТКА НА 10% ВНИЗ
	_scroll_down.click(function(){
    _html_body.animate({
        scrollTop: _window.scrollTop() + _body.height() / 10
    }, 600);
  });