这是一款基于HTML5的树叶飘落动画，树叶都是图片，并非CSS3绘制，但是树叶飘落的动画效果非常逼真。这款HTML5树叶飘落动画是基于webkit内核的，也就是说要在webkit内核的浏览器上才能使用这款动画。
在线演示源码下载
HTML代码
这是基于webkit的落叶动画
CSS代码
#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;
}
/* Defines the position and dimensions of the leafContainer p */
#leafContainer
{
position: absolute;
width: 100%;
height: 100%;
}
/* Defines the appearance, position, and dimensions of the message p */
#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;
}
p {
margin: 15px;
}
a
{
color: #5C090A;
text-decoration: none;
}
/* Sets the color of the "Dino's Gardening Service" message */
em
{
font-weight: bold;
font-style: normal;
}
.phone {
font-size: 150%;
vertical-align: middle;
}
/* This CSS rule is applied to all p elements in the leafContainer p.
It styles and animates each leafp.
*/
#leafContainer > p
{
position: absolute;
width: 100px;
height: 100px;
/* We use the following properties to apply the fade and drop animations to each leaf.
Each of these properties takes two values. These values respectively match a setting
for fade and drop.
*/
-webkit-animation-iteration-count: infinite, infinite;
-webkit-animation-direction: normal, normal;
-webkit-animation-timing-function: linear, ease-in;
}
/* This CSS rule is applied to all img elements directly inside p elements which are
directly inside the leafContainer p. In other words, it matches the 'img' elements
inside the leafps which are created in the createALeaf() function.
*/
#leafContainer > p > img {
position: absolute;
width: 100px;
height: 100px;
/* We use the following properties to adjust the clockwiseSpin or counterclockwiseSpinAndFlip
animations on each leaf.
The createALeaf function in the Leaves.js file determines whether a leaf has the
clockwiseSpin or counterclockwiseSpinAndFlip animation.
*/
-webkit-animation-iteration-count: infinite;
-webkit-animation-direction: alternate;
-webkit-animation-timing-function: ease-in-out;
-webkit-transform-origin: 50% -100%;
}
/* Hides a leaf towards the very end of the animation */
@-webkit-keyframes fade
{
/* Show a leaf while into or below 95 percent of the animation and hide it, otherwise */
0% { opacity: 1; }
95% { opacity: 1; }
100% { opacity: 0; }
}
/* Makes a leaf fall from -300 to 600 pixels in the y-axis */
@-webkit-keyframes drop
{
/* Move a leaf to -300 pixels in the y-axis at the start of the animation */
0% { -webkit-transform: translate(0px, -50px); }
/* Move a leaf to 600 pixels in the y-axis at the end of the animation */
100% { -webkit-transform: translate(0px, 650px); }
}
/* Rotates a leaf from -50 to 50 degrees in 2D space */
@-webkit-keyframes clockwiseSpin
{
/* Rotate a leaf by -50 degrees in 2D space at the start of the animation */
0% { -webkit-transform: rotate(-50deg); }
/* Rotate a leaf by 50 degrees in 2D space at the end of the animation */
100% { -webkit-transform: rotate(50deg); }
}
/* Flips a leaf and rotates it from 50 to -50 degrees in 2D space */
@-webkit-keyframes counterclockwiseSpinAndFlip
{
/* Flip a leaf and rotate it by 50 degrees in 2D space at the start of the animation */
0% { -webkit-transform: scale(-1, 1) rotate(50deg); }
/* Flip a leaf and rotate it by -50 degrees in 2D space at the end of the animation */
100% { -webkit-transform: scale(-1, 1) rotate(-50deg); }
}JavaScript代码
/* Define the number of leaves to be used in the animation */
const NUMBER_OF_LEAVES = 30;
/*
Called when the "Falling Leaves" page is completely loaded.
*/
function init()
{
/* Get a reference to the element that will contain the leaves */
var container = document.getElementById('leafContainer');
/* Fill the empty container with new leaves */
for (var i = 0; i < NUMBER_OF_LEAVES; i++)
{
container.appendChild(createALeaf());
}
}
/*
Receives the lowest and highest values of a range and
returns a random integer that falls within that range.
*/
function randomInteger(low, high)
{
return low + Math.floor(Math.random() * (high - low));
}
/*
Receives the lowest and highest values of a range and
returns a random float that falls within that range.
*/
function randomFloat(low, high)
{
return low + Math.random() * (high - low);
}
/*
Receives a number and returns its CSS pixel value.
*/
function pixelValue(value)
{
return value + 'px';
}
/*
Returns a duration value for the falling animation.
*/
function durationValue(value)
{
return value + 's';
}
/*
Uses an img element to create each leaf. "Leaves.css" implements two spin
animations for the leaves: clockwiseSpin and counterclockwiseSpinAndFlip. This
function determines which of these spin animations should be applied to each leaf.
*/
function createALeaf()
{
/* Start by creating a wrapper p, and an empty img element */
var leafp = document.createElement('p');
var image = document.createElement('img');
/* Randomly choose a leaf image and assign it to the newly created element */
image.src = 'images/realLeaf' + randomInteger(1, 5) + '.png';
leafp.style.top = "-100px";
/* Position the leaf at a random location along the screen */
leafp.style.left = pixelValue(randomInteger(0, 500));
/* Randomly choose a spin animation */
var spinAnimationName = (Math.random() < 0.5) ? 'clockwiseSpin' : 'counterclockwiseSpinAndFlip';
/* Set the -webkit-animation-name property with these values */
leafp.style.webkitAnimationName = 'fade, drop';
image.style.webkitAnimationName = spinAnimationName;
/* Figure out a random duration for the fade and drop animations */
var fadeAndDropDuration = durationValue(randomFloat(5, 11));
/* Figure out another random duration for the spin animation */
var spinDuration = durationValue(randomFloat(4, 8));
/* Set the -webkit-animation-duration property with these values */
leafp.style.webkitAnimationDuration = fadeAndDropDuration + ', ' + fadeAndDropDuration;
var leafDelay = durationValue(randomFloat(0, 5));
leafp.style.webkitAnimationDelay = leafDelay + ', ' + leafDelay;
image.style.webkitAnimationDuration = spinDuration;
// add the @@##@@ to the
leafp.appendChild(image);
/* Return this img element so it can be added to the document */
return leafp;
}
/* Calls the init function when the "Falling Leaves" page is full loaded */
window.addEventListener('load', init, false);
以上就是逼真的HTML5树叶飘落动画图文代码详解的内容，更多相关内容请关注PHP中文网（www.php.cn）！
