JSFiddle - React, Tailwind, and code Playground
HTML
<div id="ball"></div>
CSS
#ball {
background: red;
width: 50px;
height: 50px;
border-radius: 50px;
position: relative;
left: 50%;
margin-left: -25px;
}
JavaScript
// http://paulirish.com/2011/requestanimationframe-for-smart-animating/
// http://my.opera.com/emoller/blog/2011/12/20/requestanimationframe-for-smart-er-animating
// requestAnimationFrame polyfill by Erik Möller
// fixes from Paul Irish and Tino Zijdel
(function() {
var lastTime = 0;
var vendors = ['ms', 'moz', 'webkit', 'o'];
for(var x = 0; x < vendors.length && !window.requestAnimationFrame; ++x) {
window.requestAnimationFrame = window[vendors[x]+'RequestAnimationFrame'];
window.cancelAnimationFrame = window[vendors[x]+'CancelAnimationFrame']
|| window[vendors[x]+'CancelRequestAnimationFrame'];
}
if (!window.requestAnimationFrame)
window.requestAnimationFrame = function(callback, element) {
var currTime = new Date().getTime();
var timeToCall = Math.max(0, 16 - (currTime - lastTime));
var id = window.setTimeout(function() { callback(currTime + timeToCall); },
timeToCall);
lastTime = currTime + timeToCall;
return id;
};
if (!window.cancelAnimationFrame)
window.cancelAnimationFrame = function(id) {
clearTimeout(id);
};
}());
// Properties _____________________________________________
var ball = $('#ball');
var xMin = 0;
var xMax = $(window).height() - ball.height();
var pos = 0;
var dir = 1;
var speed = 8;
var fps = 60;
var interval = 1000 / fps;
// Animation Logic ________________________________________
function draw() {
setTimeout(function() {
window.requestAnimationFrame(draw);
pos = ball.position().top;
if (pos > xMax || pos < xMin) {
dir *= -1;
}
pos += (dir * speed);
ball.css('top', pos + 'px');
}, interval);
}
draw();