JS运动 - 无缝滚动和缓动动画
- 无缝滚动原理:首先先复制两张图片(第一张和第二张)放到最后面;ul绝对定位,如果ul的left值大于等于4张图片的宽度,就应该快速复原为0.
html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>无缝滚动</title>
<style>
* {
margin: 0;
padding: 0;
}
.box {
600px;
height: 200px;
background: red;
margin: 100px auto;
overflow: hidden;
position: relative;
}
ul {
list-style: none;
/*font-size: 0;*/ /* 清除图片之间的间距之方法一 */
1000%;
position: absolute;
left: 0;
top: 0;
}
li {
float: left;
}
li img {
vertical-align: bottom; /* 清除图片之间的间距之方法二 */
}
</style>
</head>
<body>
<div class="box">
<ul>
<li><img src="images/scroll01.jpg" alt=""></li>
<li><img src="images/scroll02.jpg" alt=""></li>
<li><img src="images/scroll03.jpg" alt=""></li>
<li><img src="images/scroll04.jpg" alt=""></li>
<li><img src="images/scroll01.jpg" alt=""></li>
<li><img src="images/scroll02.jpg" alt=""></li>
<li><img src="images/scroll03.jpg" alt=""></li>
<li><img src="images/scroll04.jpg" alt=""></li>
</ul>
</div>
</body>
</html>
JS
<script>
window.onload = function () {
var ul = document.getElementsByTagName("ul")[0];
var offsetX = 0;
var timer = null;
timer = setInterval(scrollDidScroll,10);
function scrollDidScroll() {
offsetX--;
offsetX = offsetX < -1200 ? 0 : offsetX;
ul.style.left = offsetX + "px";
console.log(offsetX);
}
ul.onmouseover = function () {
clearInterval(timer);
}
ul.onmouseout = function () {
timer = setInterval(scrollDidScroll,10);
}
}
</script>
效果图
- 缓动动画(减速运动)原理 : 记住公式
假如:初始值 leader = 0; 目标值 target = 400; speed = 10;公式如下
leader = leader + (target - leader) / speed;
HTML
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>滚动图</title>
<style>
* {
padding: 0;
margin: 0;
font-size: 10px;
}
ul, ol {
list-style: none;
}
.box {
490px;
height: 170px;
margin: 100px auto;
position: relative;
overflow: hidden;
}
.box ul {
position: absolute;
top: 0;
left: 0;
800%;
height: 100%;
}
.box ul li {
490px;
float: left;
}
.box ol {
position: absolute;
bottom: 10px;
left: 50%;
margin-left: -40px;
text-align: center;
}
.box ol li {
15px;
height: 15px;
line-height: 15px;
float: left;
background-color: #cccccc;
color: #ffffff;
margin-left: 10px;
cursor: pointer;
}
.box .current {
background-color: orange;
}
</style>
</head>
<body>
<div class="box">
<ul id="scrollJS">
<li><img src="0329images/01.jpg" alt=""></li>
<li><img src="0329images/02.jpg" alt=""></li>
<li><img src="0329images/03.jpg" alt=""></li>
<li><img src="0329images/04.jpg" alt=""></li>
</ul>
<ol id="olJS">
<li class="current">1</li>
<li>2</li>
<li>3</li>
<li>4</li>
</ol>
</div>
</body>
</html>
JS
<script>
window.onload = function () {
var width = 490;
var timer = null;
var leader = 0;
var scroll = document.getElementById("scrollJS");
var lis = document.getElementById("olJS").children;
for (var i=0;i<lis.length;i++) {
lis[i].index = i;
lis[i].onmouseover = function () {
clearInterval(timer);
for (var j=0;j<lis.length;j++) {
lis[j].className = "";
}
this.className = "current";
var target = -this.index * width;
timer = setInterval(function () {
leader = leader + (target - leader) / 10;
scroll.style.left = leader + "px";
},30);
}
}
}
</script>
效果图
