目录
1. 事件监听（绑定）
<button>点击</button>
<script>
const btn = document.querySelector('button')
btn.addEventListener('click', function () {
alert('早上好！')
})
</script>案例—关闭广告
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<style>
.box {
position: relative;
width: 1000px;
height: 200px;
background-color: pink;
margin: 100px auto;
text-align: center;
font-size: 50px;
line-height: 200px;
font-weight: 700;
}
.box1 {
position: absolute;
right: 20px;
top: 10px;
width: 20px;
height: 20px;
background-color: skyblue;
text-align: center;
line-height: 20px;
font-size: 16px;
cursor: pointer;
}
</style>
</head>
<body>
<div class="box">
我是广告
<div class="box1">X</div>
</div>
<script>
// 1. 获取事件源
const box1 = document.querySelector('.box1')
// 关闭的是大盒子
const box = document.querySelector('.box')
// 2. 事件侦听
box1.addEventListener('click', function () {
box.style.display = 'none'
})
</script>
</body>
</html>案例-随机点名
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<style>
* {
margin: 0;
padding: 0;
}
h2 {
text-align: center;
}
.box {
width: 600px;
margin: 50px auto;
display: flex;
font-size: 25px;
line-height: 40px;
}
.qs {
width: 450px;
height: 40px;
color: red;
}
.btns {
text-align: center;
}
.btns button {
width: 120px;
height: 35px;
margin: 0 50px;
}
</style>
</head>
<body>
<h2>随机点名</h2>
<div class="box">
<span>名字是：</span>
<div class="qs">这里显示姓名</div>
</div>
<div class="btns">
<button class="start">开始</button>
<button class="end">结束</button>
</div>
<script>
// 数据数组
const arr = ['马超', '黄忠', '赵云', '关羽', '张飞']
const qs = document.querySelector('.qs')
const start = document.querySelector('.start')
let timerId = 0 //用来关闭计时器，如果声明在函数里，是个局部变量，函数外无法调用
let random = 0
//1.开始模块，随机显示名字
start.addEventListener('click', function () {
timerId = setInterval(function () {
random = parseInt(Math.random() * arr.length)
// console.log(arr[random]);
qs.innerHTML = arr[random]
}, 35)
if (arr.length === 1) { //只剩最后一位未抽 开始与结束按钮禁用
// start.disabled = true
// end.disabled = true
start.disabled = end.disabled = true
}
})
// 2.关闭模块
const end = document.querySelector('.end')
end.addEventListener('click', function () {
clearInterval(timerId)
arr.splice(random, 1) //点过的同学不重复点
})
</script>
</body>
</html>
2. 事件类型
2.1 鼠标事件
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>轮播图点击切换</title>
<style>
* {
box-sizing: border-box;
}
.slider {
width: 560px;
height: 400px;
overflow: hidden;
}
.slider-wrapper {
width: 100%;
height: 320px;
}
.slider-wrapper img {
width: 100%;
height: 100%;
display: block;
}
.slider-footer {
height: 80px;
background-color: rgb(100, 67, 68);
padding: 12px 12px 0 12px;
position: relative;
}
.slider-footer .toggle {
position: absolute;
right: 0;
top: 12px;
display: flex;
}
.slider-footer .toggle button {
margin-right: 12px;
width: 28px;
height: 28px;
appearance: none;
border: none;
background: rgba(255, 255, 255, 0.1);
color: #fff;
border-radius: 4px;
cursor: pointer;
}
.slider-footer .toggle button:hover {
background: rgba(255, 255, 255, 0.2);
}
.slider-footer p {
margin: 0;
color: #fff;
font-size: 18px;
margin-bottom: 10px;
}
.slider-indicator {
margin: 0;
padding: 0;
list-style: none;
display: flex;
align-items: center;
}
.slider-indicator li {
width: 8px;
height: 8px;
margin: 4px;
border-radius: 50%;
background: #fff;
opacity: 0.4;
cursor: pointer;
}
.slider-indicator li.active {
width: 12px;
height: 12px;
opacity: 1;
}
</style>
</head>
<body>
<div class="slider">
<div class="slider-wrapper">
<img src="./images/slider01.jpg" alt="" />
</div>
<div class="slider-footer">
<p>对人类来说会不会太超前了？</p>
<ul class="slider-indicator">
<li class="active"></li>
<li></li>
<li></li>
<li></li>
<li></li>
<li></li>
<li></li>
<li></li>
</ul>
<div class="toggle">
<button class="prev"><</button>
<button class="next">></button>
</div>
</div>
</div>
<script>
// 1. 初始数据
const data = [
{ url: './images/slider01.jpg', title: '对人类来说会不会太超前了？', color: 'rgb(100, 67, 68)' },
{ url: './images/slider02.jpg', title: '开启剑与雪的黑暗传说！', color: 'rgb(43, 35, 26)' },
{ url: './images/slider03.jpg', title: '真正的jo厨出现了！', color: 'rgb(36, 31, 33)' },
{ url: './images/slider04.jpg', title: '李玉刚：让世界通过B站看到东方大国文化', color: 'rgb(139, 98, 66)' },
{ url: './images/slider05.jpg', title: '快来分享你的寒假日常吧~', color: 'rgb(67, 90, 92)' },
{ url: './images/slider06.jpg', title: '哔哩哔哩小年YEAH', color: 'rgb(166, 131, 143)' },
{ url: './images/slider07.jpg', title: '一站式解决你的电脑配置问题！！！', color: 'rgb(53, 29, 25)' },
{ url: './images/slider08.jpg', title: '谁不想和小猫咪贴贴呢！', color: 'rgb(99, 72, 114)' },
]
const img = document.querySelector('.slider-wrapper img')
const p = document.querySelector('.slider-footer p')
const footer = document.querySelector('.slider-footer')
//1.右侧按钮业务
const next = document.querySelector('.next')
let i = 0 //信号量，控制播放图片张数
next.addEventListener('click', function () {
// console.log('11');
i++
if (i === data.length) {
i = 0
}
// console.log(data[i]);
toggle()
})
//2.左侧按钮业务
const prev = document.querySelector('.prev')
prev.addEventListener('click', function () {
i--
if (i < 0) {
i = data.length - 1 //最后一张图的索引号
}
toggle()
})
// 声明一个渲染函数作为复用
function toggle() {
img.src = data[i].url
p.innerHTML = data[i].title
footer.style.backgroundColor = data[i].color
document.querySelector('.slider-indicator .active').classList.remove('active')
document.querySelector(`.slider-indicator li:nth-child(${i + 1})`).classList.add('active')
}
// 3.定时器—自动播放
let timerId = setInterval(function () {
//利用js自动调用点击事件,调用函数要加小括号
next.click()
}, 1000)
// 4.鼠标经过大盒子，停止计时器
const slider = document.querySelector('.slider')
slider.addEventListener('mouseenter', function () {
clearInterval(timerId)
})
// 5.鼠标离开大盒子，开始计时器
slider.addEventListener('mouseleave', function () {
timerId = setInterval(function () {
next.click()
}, 1000)
})
</script>
</body>
</html>2.2 焦点事件
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<style>
* {
margin: 0;
padding: 0;
box-sizing: border-box;
}
ul {
list-style: none;
}
.mi {
position: relative;
width: 223px;
margin: 100px auto;
}
.mi input {
width: 223px;
height: 48px;
padding: 0 10px;
font-size: 14px;
line-height: 48px;
border: 1px solid #e0e0e0;
outline: none;
}
.mi .search {
border: 1px solid #ff6700;
}
.result-list {
display: none;
position: absolute;
left: 0;
top: 48px;
width: 223px;
border: 1px solid #ff6700;
border-top: 0;
background: #fff;
}
.result-list a {
display: block;
padding: 6px 15px;
font-size: 12px;
color: #424242;
text-decoration: none;
}
.result-list a:hover {
background-color: #eee;
}
</style>
</head>
<body>
<div class="mi">
<input type="search" placeholder="小米笔记本">
<ul class="result-list">
<li><a href="#">全部商品</a></li>
<li><a href="#">小米11</a></li>
<li><a href="#">小米10S</a></li>
<li><a href="#">小米笔记本</a></li>
<li><a href="#">小米手机</a></li>
<li><a href="#">黑鲨4</a></li>
<li><a href="#">空调</a></li>
</ul>
</div>
<script>
const input = document.querySelector('[type=search]') //有多种文本框可以选择类型
const ul = document.querySelector('.result-list')
// 获得焦点
input.addEventListener('focus', function () {
ul.style.display = 'block'
input.classList.add('search')
})
// 失去焦点
input.addEventListener('blur', function () {
ul.style.display = 'none'
input.classList.remove('search')
})
</script>
</body>
</html>2.3 文本事件
input.addEventListener('input', function () {
console.log(input.value);
})3. 事件对象
<button>点击</button>
<input type="text">
<script>
const btn = document.querySelector('button')
btn.addEventListener('click', function (e) {
console.log(e);
})
const input = document.querySelector('input')
input, addEventListener('keyup', function (e) {
// console.log(e.key);
if (e.key === 'Enter') {
console.log('回车键');
}
})
</script>案例—评论回车发布
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>评论回车发布</title>
<style>
.wrapper {
min-width: 400px;
max-width: 800px;
display: flex;
justify-content: flex-end;
}
.avatar {
width: 48px;
height: 48px;
border-radius: 50%;
overflow: hidden;
background: url(./images/avatar.jpg) no-repeat center / cover;
margin-right: 20px;
}
.wrapper textarea {
outline: none;
border-color: transparent;
resize: none;
background: #f5f5f5;
border-radius: 4px;
flex: 1;
padding: 10px;
transition: all 0.5s;
height: 30px;
}
.wrapper textarea:focus {
border-color: #e4e4e4;
background: #fff;
height: 50px;
}
.wrapper button {
background: #00aeec;
color: #fff;
border: none;
border-radius: 4px;
margin-left: 10px;
width: 70px;
cursor: pointer;
}
.wrapper .total {
margin-right: 80px;
color: #999;
margin-top: 5px;
opacity: 0;
transition: all 0.5s;
}
.list {
min-width: 400px;
max-width: 800px;
display: flex;
}
.list .item {
width: 100%;
display: flex;
}
.list .item .info {
flex: 1;
border-bottom: 1px dashed #e4e4e4;
padding-bottom: 10px;
}
.list .item p {
margin: 0;
}
.list .item .name {
color: #FB7299;
font-size: 14px;
font-weight: bold;
}
.list .item .text {
color: #333;
padding: 10px 0;
}
.list .item .time {
color: #999;
font-size: 12px;
}
</style>
</head>
<body>
<div class="wrapper">
<i class="avatar"></i>
<textarea id="tx" placeholder="发一条友善的评论" rows="2" maxlength="200"></textarea>
<button>发布</button>
</div>
<div class="wrapper">
<span class="total">0/200字</span>
</div>
<div class="list">
<div class="item" style="display: none;">
<i class="avatar"></i>
<div class="info">
<p class="name">清风徐来</p>
<p class="text">大家都辛苦啦，感谢各位大大的努力，能圆满完成真是太好了[笑哭][支持]</p>
<p class="time">2022-10-10 20:29:21</p>
</div>
</div>
</div>
<script>
const tx = document.querySelector('#tx')
const total = document.querySelector('.total')
const item = document.querySelector('.item')
const text = document.querySelector('.text')
// 1.获得焦点，total显示
tx.addEventListener('focus', function () {
total.style.opacity = 1
})
// 2.获得焦点，total显示
tx.addEventListener('blur', function () {
total.style.opacity = 0
})
// 3.检测用户输入
tx.addEventListener('input', function () {
total.innerHTML = `${tx.value.length}/200字`
})
// 4.按下回车发布评论
tx.addEventListener('keyup', function (e) {
if (e.key === 'Enter') { //E要大写
//去除字符串两侧的空格
if (tx.value.trim() !== '') {//if (tx.value.trim())
item.style.display = 'block'
text.innerHTML = tx.value.trim()
}
// 按下回车后，结束，清空文本域内容，将字符统计复原
tx.value = ''
total.innerHTML = '0/200字'
}
})
</script>
</body>
</html>4. 环境对象
5. 回调函数
当条件成立，调用B
6. 综合案例—tab栏切换
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>tab栏切换</title>
<style>
* {
margin: 0;
padding: 0;
}
.tab {
width: 590px;
height: 340px;
margin: 20px;
border: 1px solid #e4e4e4;
}
.tab-nav {
width: 100%;
height: 60px;
line-height: 60px;
display: flex;
justify-content: space-between;
}
.tab-nav h3 {
font-size: 24px;
font-weight: normal;
margin-left: 20px;
}
.tab-nav ul {
list-style: none;
display: flex;
justify-content: flex-end;
}
.tab-nav ul li {
margin: 0 20px;
font-size: 14px;
}
.tab-nav ul li a {
text-decoration: none;
border-bottom: 2px solid transparent;
color: #333;
}
.tab-nav ul li a.active {
border-color: #e1251b;
color: #e1251b;
}
.tab-content {
padding: 0 16px;
}
.tab-content .item {
display: none;
}
.tab-content .item.active {
display: block;
}
</style>
</head>
<body>
<div class="tab">
<div class="tab-nav">
<h3>每日特价</h3>
<ul>
<li><a class="active" href="javascript:;">精选</a></li>
<li><a href="javascript:;">美食</a></li>
<li><a href="javascript:;">百货</a></li>
<li><a href="javascript:;">个护</a></li>
<li><a href="javascript:;">预告</a></li>
</ul>
</div>
<div class="tab-content">
<div class="item active"><img src="./images/tab00.png" alt="" /></div>
<div class="item"><img src="./images/tab01.png" alt="" /></div>
<div class="item"><img src="./images/tab02.png" alt="" /></div>
<div class="item"><img src="./images/tab03.png" alt="" /></div>
<div class="item"><img src="./images/tab04.png" alt="" /></div>
</div>
</div>
<script>
const as = document.querySelectorAll('.tab-nav a')
// console.log(as);
for (let i = 0; i < as.length; i++) {
as[i].addEventListener('mouseenter', function () {
// console.log('鼠标经过');
document.querySelector('.tab-nav .active').classList.remove('active')
// document.querySelector(`.tab-nav li:nth-child(${i + 1}) a`).classList.add('active')
this.classList.add('active') //this指的是as[i]
document.querySelector('.tab-content .active').classList.remove('active')
document.querySelector(`.tab-content .item:nth-child(${i + 1})`).classList.add('active')
})
}
</script>
</body>
</html>