一、滚动事件和加载事件
1.1滚动事件
1.2 加载事件
二、元素大小和位置
2.1 scroll家族(返回值不带单位)
2.2 offset家族
2.3 client家族
三、实践——轮播图
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>QQ音乐轮播图</title>
<style>
* {
margin: 0;
padding: 0;
box-sizing: border-box;
}
li {
list-style: none;
}
.main {
width: 700px;
margin: auto;
background: #000;
}
.slides {
height: 320px;
position: relative;
}
.slides ul li {
/* display: none; */
position: absolute;
top: 0;
left: 0;
opacity: 0;
/* 这里实现淡入淡出的关键 */
transition: all .3s;
}
.slides li.active {
/* display: block; */
opacity: 1;
}
.slides .extra {
width: 700px;
height: 53px;
line-height: 53px;
position: absolute;
bottom: 0px;
background-color: rgba(0, 0, 0, 0.8);
z-index: 10;
}
.slides .extra h3 {
width: 82%;
margin: 0;
margin-right: 20px;
padding-left: 20px;
color: #98E404;
font-size: 28px;
float: left;
font-weight: 500;
font-family: "Microsoft Yahei", Tahoma, Geneva;
}
.slides .extra a {
width: 30px;
height: 29px;
display: block;
float: left;
margin-top: 12px;
margin-right: 3px;
background-image: url(./assets/icon_focus_switch.png);
}
.slides .extra .prev {
background-position: 0 0;
}
.slides .extra .prev:hover {
background-position: -30px 0;
}
.slides .extra .next {
background-position: -60px 0;
}
.slides .extra .next:hover {
background-position: -90px 0;
}
.indicator {
padding: 10px 0;
}
.indicator ul {
list-style-type: none;
margin: 0 0 0 4px;
padding: 0;
overflow: hidden;
}
.indicator ul li {
position: relative;
float: left;
width: 60px;
margin: 0 4px 0 5px;
text-align: center;
cursor: pointer;
}
.indicator li img {
display: block;
border: 0;
text-align: center;
width: 60px;
}
.indicator li .mask {
width: 60px;
height: 60px;
position: absolute;
top: 0;
left: 0;
background-color: rgba(0, 0, 0, 0.4);
}
.indicator li .border {
display: none;
width: 54px;
position: absolute;
bottom: 0;
left: 0;
z-index: 20;
border: 3px solid #98E404;
}
/* li里面的mask 和 border 刚开始都是显示的 */
/* 我们写一个样式css */
.indicator .active .mask {
display: none;
}
.indicator .active .border {
display: block;
}
</style>
</head>
<body>
<div class="main">
<div class="slides">
<ul>
<li class="active"><a href="#"><img src="./assets/b_01.jpg" alt="第1张图的描述信息"></a></li>
<li><a href="#"><img src="./assets/b_02.jpg" alt="第2张图的描述信息"></a></li>
<li><a href="#"><img src="./assets/b_03.jpg" alt="第3张图的描述信息"></a></li>
<li><a href="#"><img src="./assets/b_04.jpg" alt="第4张图的描述信息"></a></li>
<li><a href="#"><img src="./assets/b_05.jpg" alt="第5张图的描述信息"></a></li>
<li><a href="#"><img src="./assets/b_06.jpg" alt="第6张图的描述信息"></a></li>
<li><a href="#"><img src="./assets/b_07.jpg" alt="第7张图的描述信息"></a></li>
<li><a href="#"><img src="./assets/b_08.jpg" alt="第8张图的描述信息"></a></li>
<li><a href="#"><img src="./assets/b_09.jpg" alt="第9张图的描述信息"></a></li>
<li><a href="#"><img src="./assets/b_10.jpg" alt="第9张图的描述信息"></a></li>
</ul>
<div class="extra">
<h3>第1张图的描述</h3>
<a class="prev" href="javascript:;"></a>
<a class="next" href="javascript:;"></a>
</div>
</div>
<div class="indicator">
<ul>
<li class="active">
<img src="assets/s_01.jpg">
<span class="mask"></span>
<span class="border"></span>
</li>
<li>
<img src="assets/s_02.jpg">
<span class="mask"></span>
<span class="border"></span>
</li>
<li>
<img src="assets/s_03.jpg">
<span class="mask"></span>
<span class="border"></span>
</li>
<li>
<img src="assets/s_04.jpg">
<span class="mask"></span>
<span class="border"></span>
</li>
<li>
<img src="assets/s_05.jpg">
<span class="mask"></span>
<span class="border"></span>
</li>
<li>
<img src="assets/s_06.jpg">
<span class="mask"></span>
<span class="border"></span>
</li>
<li>
<img src="assets/s_07.jpg">
<span class="mask"></span>
<span class="border"></span>
</li>
<li>
<img src="assets/s_08.jpg">
<span class="mask"></span>
<span class="border"></span>
</li>
<li>
<img src="assets/s_09.jpg">
<span class="mask"></span>
<span class="border"></span>
</li>
<li>
<img src="assets/s_10.jpg">
<span class="mask"></span>
<span class="border"></span>
</li>
</ul>
</div>
</div>
<script>
// 轮播图开始啦
let lis = document.querySelectorAll('.indicator li')
let piclis = document.querySelectorAll('.slides ul li')
let text = document.querySelector('.extra h3')
let next = document.querySelector('.next')
let prev = document.querySelector('.prev')
let main = document.querySelector('.main')
for(let i=0;i<lis.length;i++){
lis[i].addEventListener('mouseenter',function(){
document.querySelector('.indicator .active').classList.remove('active')
this.classList.add('active')
document.querySelector('.slides .active').classList.remove('active')
piclis[i].classList.add('active')
index=i
text.innerHTML=`第${i+1}张图的描述`
})
}
let index=0
next.addEventListener('click',function(){
index++
common()
})
prev.addEventListener('click',function(){
index--
if(index<0){
index=lis.length-1
}
common()
})
function common(){
index=index % lis.length
document.querySelector('.indicator .active').classList.remove('active')
lis[index].classList.add('active')
document.querySelector('.slides .active').classList.remove('active')
piclis[index].classList.add('active')
text.innerHTML=`第${index+1}张图的描述`
}
let timer=setInterval(function(){
next.click()
},1000)
main.addEventListener('mouseenter',function(){
clearInterval(timer)
})
main.addEventListener('mouseleave',function(){
timer=setInterval(function(){
next.click()
},1000)
})
</script>
</body>
</html>