实现如图所示的东西效果（落叶下落）：
html代码：
<!DOCTYPE html><html><head> <title>HTML5树叶飘落动画</title> <meta charset="utf-8"> <meta name="viewport" content="width=500px, initial-scale=0.64"> <link rel="stylesheet" href="leaves.css" type="text/css"> <script src="leaves.js" type="text/javascript"></script></head><body> <div id="container"> <div id="leafContainer"></div> <div id="message"> <em>这是基于webkit的落叶动画</em> </div> </div> </body></html>css代码：body{ background-color: #4E4226;}#container { position: relative; height: 700px; width: 500px; margin: 10px auto; overflow: hidden; border: 4px solid #5C090A; background: #4E4226 url('images/backgroundLeaves.jpg') no-repeat top left;}#leafContainer { position: absolute; width: 100%; height: 100%;}#message{ position: absolute; top: 160px; width: 100%; height: 300px; background:transparent url('images/textBackground.png') repeat-x center; color: #5C090A; font-size: 220%; font-family: 'Georgia'; text-align: center; padding: 20px 10px; -webkit-box-sizing: border-box; -webkit-background-size: 100% 100%; z-index: 1;}em { font-weight: bold; font-style: normal;}#leafContainer > div { position: absolute; width: 100px; height: 100px; -webkit-animation-iteration-count: infinite; -webkit-animation-direction: normal; -webkit-animation-timing-function: linear;}#leafContainer > div > img { position: absolute; width: 100px; height: 100px; -webkit-animation-iteration-count: infinite; -webkit-animation-direction: alternate; -webkit-animation-timing-function: ease-in-out; -webkit-transform-origin: 50% -100%;}@-webkit-keyframes fade{ 0% { opacity: 1; } 95% { opacity: 1; } 100% { opacity: 0; }}@-webkit-keyframes drop{ 0% { -webkit-transform: translate(0px, -50px); } 100% { -webkit-transform: translate(0px, 650px); }}@-webkit-keyframes clockwiseSpin{ 0% { -webkit-transform: rotate(-50deg); } 100% { -webkit-transform: rotate(50deg); }}@-webkit-keyframes counterclockwiseSpinAndFlip { 0% { -webkit-transform: scale(-1, 1) rotate(50deg); } 100% { -webkit-transform: scale(-1, 1) rotate(-50deg); }}js代码：const NUMBER_OF_LEAVES = 30;function init(){ var container = document.getElementById('leafContainer'); for (var i = 0; i < NUMBER_OF_LEAVES; i++) { container.appendChild(createALeaf()); }}function randomInteger(low, high){ return low + Math.floor(Math.random() * (high - low));}function randomFloat(low, high){ return low + Math.random() * (high - low);}function pixelValue(value){ return value + 'px';}function durationValue(value){ return value + 's';}function createALeaf(){ var leafDiv = document.createElement('div'); leafDiv.style.top = "-100px"; leafDiv.style.left = pixelValue(randomInteger(0, 500)); leafDiv.style.webkitAnimationName = 'fade, drop'; var fadeAndDropDuration = durationValue(randomFloat(5, 11)); leafDiv.style.webkitAnimationDuration = fadeAndDropDuration + ', ' + fadeAndDropDuration; var leafDelay = durationValue(randomFloat(0, 5)); leafDiv.style.webkitAnimationDelay = leafDelay + ', ' + leafDelay; var image = document.createElement('img'); image.src = 'images/realLeaf' + randomInteger(1, 5) + '.png'; var spinAnimationName = (Math.random() < 0.5) ? 'clockwiseSpin' : 'counterclockwiseSpinAndFlip'; image.style.webkitAnimationName = spinAnimationName; var spinDuration = durationValue(randomFloat(4, 8)); image.style.webkitAnimationDuration = spinDuration; leafDiv.appendChild(image); return leafDiv;}window.addEventListener('load', init, false);PS：下面看下html5 canvas处理连续帧图片,下面的代码基于IE8以上
<!DOCTYPE html><html><head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0, minimum-scale=1.0, maximum-scale=1.0, user-scalable=no"/><title>Canvas Demo</title><script>var canvas = null;//初始化参数var img = null;var ctx = null;var imageReady = false;window.onload = function() { var canvas = document.getElementById("animation_canvas"); canvas.width = canvas.parentNode.clientWidth; canvas.height = canvas.parentNode.clientHeight; if (!canvas.getContext) { console.log("Canvas not supported. Please install a HTML5 compatible browser."); return; } // get 2D context of canvas and draw rectangel ctx = canvas.getContext("2d"); ctx.fillStyle="black"; ctx.fillRect(0, 0, canvas.width, canvas.height); console.log(canvas.height); img = document.createElement('img'); img.src = "images/ab0.png"; img.onload = loaded();} //保证只有图像加载后才开始循环动画function loaded() { imageReady = true; setTimeout( update, 1000/3);//添加3帧每秒间隔计时器}function redraw() { ctx.fillStyle="black"; ctx.fillRect(0, 0, 460, 460); ctx.drawImage(img, 0, 0, 232, 180);} //为了让图片以规定的速度动画，我们必须追踪已经经过的时间，然后根据分配给每帧的时间播放帧。基本步骤是：//1、按每秒几帧设置动画速度(msPerFrame)。//2、当你循环游戏时，计算一下自最后一帧以后已经经过了多少时间（delta）。//3、如果已经经过的时间足够把动画帧播完，那么播放这一帧并设置累积delta为0。//4、如果已经经过的时间不够，那么记住（累积）delta时间（acDelta）。var frame = 0;var lastUpdateTime = 0;var acDelta = 0;var msPerFrame = 200;function update() { requestAnimFrame(update); var delta = Date.now() - lastUpdateTime; //console.log(Date.now(),lastUpdateTime); if (acDelta > msPerFrame){ acDelta = 0; redraw(); img.src='images/ab'+frame+'.png'; frame++; if(frame >= 3) frame = 0; //当绘制后且帧推进完，计时器就会重置。 }else{ acDelta += delta; } lastUpdateTime = Date.now();}//requestAnimFrame的作用基本上就是setTimeout，但浏览器知道你正在渲染帧，所以它可以优化绘制循环，以及如何与剩下的页面回流。//在某些情况下，setTimeout比requestAnimFrame更好用，特别是对于手机。//以下是在不同的浏览器上调用requestAnimFrame的情况也不同，标准的检测方法如下：window.requestAnimFrame = (function(){ return window.requestAnimationFrame || window.webkitRequestAnimationFrame || window.mozRequestAnimationFrame || window.oRequestAnimationFrame || window.msRequestAnimationFrame || function( callback ){ window.setTimeout(callback, 1000 / 3); //如果requestAnimFrame支持不可用，还是可以用回内置的setTimeout。 };})();</script></head><body style="position:absolute;margin:0;padding:0;width:100%;height:100%;"> <canvas id="animation_canvas"></canvas></body></html>总结
以上所述是小编给大家介绍的基于HTML5+Webkit实现树叶飘落动画，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对武林网网站的支持！
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