<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>最简单的轮播效果</title>
<style>
* {
margin: 0;
padding: 0
}
.box {
width: 500px;
height: 300px;
border: 1px solid #ccc;
margin: 100px auto;
padding: 5px;
}
.inner {
width: 500px;
height: 300px;
position: relative;
overflow: hidden;
}
.inner img {
width: 500px;
height: 300px;
vertical-align: top
}
ul {
width: 1000%;
position: absolute;
list-style: none;
left: 0;
top: 0;
}
.inner li {
float: left;
}
ol {
position: absolute;
height: 20px;
right: 20px;
bottom: 20px;
text-align: center;
padding: 5px;
}
ol li {
display: inline-block;
width: 20px;
height: 20px;
line-height: 20px;
background-color: #fff;
margin: 5px;
cursor: pointer;
}
ol .current {
background-color: red;
}
#arr {
display: none;
}
#arr span {
width: 40px;
height: 40px;
position: absolute;
left: 5px;
top: 50%;
margin-top: -20px;
background: #fff;
cursor: pointer;
line-height: 40px;
text-align: center;
font-weight: bold;
font-family: '黑体';
font-size: 30px;
color: #000;
opacity: 0.5;
border: 1px solid #fff;
}
#arr #right {
right: 5px;
left: auto;
}
</style>
</head>
<body>
<div class="box" id="box">
<div class="inner">
<!--轮播图-->
<ul>
<li>
<a href=" ">
<img src="img/微信图片_20200620195232.jpg" alt=""></a>
</li>
<li>
<a href="#">
<img src="img/微信图片_20200620195232.jpg" alt=""><a>
</li>
<li>
<a href="#">
<img src="img/微信图片_20200620195232.jpg" alt=""><a>
</li>
<li>
<a href="#">
<img src="img/微信图片_20200620195232.jpg" alt=""></a>
</li>
<li>
<a href="#">
<img src="img/微信图片_20200620195232.jpg" alt=""></a>
</li>
</ul>
<ol class="bar">
</ol>
<!--左右焦点-->
<div id="arr">
<span id="left">
<
</span>
<span id="right">
>
</span>
</div>
</div>
</div>
<script>
/**
*
* @param id 传入元素的id
* @returns {HTMLElement | null} 返回标签对象，方便获取元素
*/
function my$(id) {
return document.getElementById(id);
}
//获取各元素，方便操作
var box = my$("box");
var inner = box.children[0];
var ulObj = inner.children[0];
var list = ulObj.children;
var olObj = inner.children[1];
var arr = my$("arr");
var imgWidth = inner.offsetWidth;
var right = my$("right");
var pic = 0;
//根据li个数，创建小按钮
for(var i = 0; i < list.length; i++) {
var liObj = document.createElement("li");
olObj.appendChild(liObj);
liObj.innerText = (i + 1);
liObj.setAttribute("index", i);
//为按钮注册mouseover事件
liObj.onmouseover = function() {
//先清除所有按钮的样式
for(var j = 0; j < olObj.children.length; j++) {
olObj.children[j].removeAttribute("class");
}
this.className = "current";
pic = this.getAttribute("index");
animate(ulObj, -pic * imgWidth);
}
}
//设置ol中第一个li有背景颜色
olObj.children[0].className = "current";
//克隆一个ul中第一个li,加入到ul中的最后=====克隆
ulObj.appendChild(ulObj.children[0].cloneNode(true));
var timeId = setInterval(onmouseclickHandle, 1000);
//左右焦点实现点击切换图片功能
box.onmouseover = function() {
arr.style.display = "block";
clearInterval(timeId);
};
box.onmouseout = function() {
arr.style.display = "none";
timeId = setInterval(onmouseclickHandle, 1000);
};
right.onclick = onmouseclickHandle;
function onmouseclickHandle() {
//如果pic的值是5,恰巧是ul中li的个数-1的值,此时页面显示第六个图片,而用户会认为这是第一个图,
//所以,如果用户再次点击按钮,用户应该看到第二个图片
if(pic == list.length - 1) {
//如何从第6个图,跳转到第一个图
pic = 0; //先设置pic=0
ulObj.style.left = 0 + "px"; //把ul的位置还原成开始的默认位置
}
pic++; //立刻设置pic加1,那么此时用户就会看到第二个图片了
animate(ulObj, -pic * imgWidth); //pic从0的值加1之后,pic的值是1,然后ul移动出去一个图片
//如果pic==5说明,此时显示第6个图(内容是第一张图片),第一个小按钮有颜色,
if(pic == list.length - 1) {
//第五个按钮颜色干掉
olObj.children[olObj.children.length - 1].className = "";
//第一个按钮颜色设置上
olObj.children[0].className = "current";
} else {
//去掉所有的小按钮的背景颜色
for(var i = 0; i < olObj.children.length; i++) {
olObj.children[i].removeAttribute("class");
}
olObj.children[pic].className = "current";
}
}
left.onclick = function() {
if(pic == 0) {
pic = list.length - 1;
ulObj.style.left = -pic * imgWidth + "px";
}
pic--;
animate(ulObj, -pic * imgWidth);
for(var i = 0; i < olObj.children.length; i++) {
olObj.children[i].removeAttribute("class");
}
//当前的pic索引对应的按钮设置颜色
olObj.children[pic].className = "current";
};
//设置任意的一个元素,移动到指定的目标位置
function animate(element, target) {
clearInterval(element.timeId);
//定时器的id值存储到对象的一个属性中
element.timeId = setInterval(function() {
//获取元素的当前的位置,数字类型
var current = element.offsetLeft;
//每次移动的距离
var step = 10;
step = current < target ? step : -step;
//当前移动到位置
current += step;
if(Math.abs(current - target) > Math.abs(step)) {
element.style.left = current + "px";
} else {
//清理定时器
clearInterval(element.timeId);
//直接到达目标
element.style.left = target + "px";
}
}, 10);
}
</script>
</body>
</html>
