JavaScript-DOM实战案例
一、window定时器
1.window定时器方法
有时我们并不想立即执行一个函数，而是等待特定一段时间之后再执行，我们称之为“计划调用（scheduling a call）”。
目前有两种方式可以实现：
-
setTimeout允许我们将函数推迟到一段时间间隔之后再执行。 -
setInterval允许我们重复运行一个函数，从一段时间间隔之后开始运行，之后以该时间间隔连续重复运行该函数。
并且通常情况下有提供对应的取消方法：
clearTimeout：取消setTimeout的定时器；clearInterval：取消setInterval的定时器；
大多数运行环境都有内置的调度程序，并且提供了这些方法：
- 目前来讲，所有浏览器以及
Node.js都支持这两个方法； - 所以我们后续学习Node的时候，也可以在Node中使用它们；
2.setTimeout的使用
setTimeout的语法如下：
let timerId = setTimeout(func|code, [delay], [arg1], [arg2], ...)
func|code：想要执行的函数或代码字符串。- 一般传入的都是函数，由于某些历史原因，支持传入
代码字符串，但是不建议这样做；
- 一般传入的都是函数，由于某些历史原因，支持传入
delay：执行前的延时，以毫秒为单位（1000 毫秒 = 1 秒），默认值是 0；- arg1，arg2…：要传入被执行函数（或代码字符串）的参数列表；
clearTimeout方法：
setTimeout在调用时会返回一个“定时器标识符（timer identifier）”，我们可以使用它来取消执行
function showTime() {
console.log(new Date().toISOString());
setTimeout("showTime()", 1000);
}
showTime();
// 或者
function showTime() {
console.log(new Date().toISOString());
setTimeout(showTime, 1000);
}
showTime();
3.setInterval的使用
setInterval 方法和 setTimeout 的语法相同：
- 所有参数的意义也是相同的；
- 不过与 setTimeout 只执行一次不同，setInterval 是每间隔给定的时间周期性执行；
clearInterval方法：
- setInterval也会返回一个“定时器标识符（timer identifier）”，我们可以通过clearInterval来取消这个定时器。
关于定时器还有一些
宏任务相关的概念，我们会在JavaScript高级中讲解。
二、案例实战
1.轮播消息提示
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>Documenttitle>
<style>
.tip-bar {
display: inline-flex;
align-items: center;
height: 30px;
background-color: rgba(0,0,0,.4);
border-radius: 16px;
}
img {
width: 30px;
height: 30px;
border-radius: 50%;
margin-right: 5px;
}
span {
font-size: 13px;
color: white;
margin-right: 8px;
}
style>
head>
<body>
<div class="tip-bar">
<img src="https://bfs.biyao.com/group1/M01/A2/67/rBACVGA_iOuAYaTxAAAPbted3yE165.png" alt="">
<span>183***138对这件商品感兴趣span>
div>
<script>
// 1.从服务器拿到数据ajax/fetch请求
let tipList = [
{
icon: 'https://bfs.biyao.com/group1/M01/A6/97/rBACYWBCHqyAFH5tAAANZXX5Eww646.png',
title: 'coderwhy对这件商品感兴趣'
},
{
icon: 'https://bfs.biyao.com/group1/M01/A2/67/rBACVGA_iOuAYaTxAAAPbted3yE165.png',
title: '123***814对这件商品感兴趣'
},
{
icon: 'https://bfs.biyao.com/group1/M00/7F/4E/rBACYV16HseAP-PnAAAW9bbVoKE463.png',
title: '刘军对这件商品感兴趣'
}
]
// 2.动态的切换数据
// 2.1.获取元素
var tipBar = document.querySelector(".tip-bar")
var imgEl = tipBar.querySelector("img")
var spanEl = tipBar.querySelector("span")
// 2.2.3s切换一次数据
var currentIndex = 0 // 记录当前展示到的索引位置
setInterval(function() {
// 1> 根据索引获取item
var tipItem = tipList[currentIndex]
// 2> 给DOM设置内容
imgEl.src = tipItem.icon
spanEl.textContent = tipItem.title
// 3> 重新计算索引
currentIndex++
if (currentIndex === tipList.length) {
currentIndex = 0
}
}, 3000)
// 随机
// Math.floor(Math.random() * tipList.length)
script>
body>
html>
2.关闭隐藏信息
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>Documenttitle>
<style>
.top-bar {
display: flex;
flex-direction: row;
align-items: center;
height: 45px;
width: 375px;
background-color: black;
/* 关键 */
overflow: hidden;
transition: all .5s ease-out;
}
.delete {
display: flex;
flex-direction: row;
justify-content: center;
align-items: center;
height: 100%;
width: 30px;
cursor: pointer;
}
.delete img {
height: 10px;
width: 10px;
}
.logo {
height: 30px;
width: 30px;
margin-left:3px;
margin-right: 30px;
cursor: pointer;
}
span {
color: white;
font-size: 14px;
flex: 1;
white-space: nowrap;
overflow: hidden;
text-overflow: ellipsis;
}
.btn {
width: 94px;
height: 100%;
line-height: 45px;
text-align: center;
font-size: 14px;
color: #fff;
background-color: #F63515;
}
style>
head>
<body>
<div class="top-bar">
<div class="delete">
<img src="./img/delete.png" alt="">
div>
<img class="logo" src="./img/logo.png" alt="">
<span>打开京东App,购物更轻松span>
<div class="btn">立即打开div>
div>
<script>
// 1.获取元素
var topBar = document.querySelector(".top-bar")
var deleteEl = topBar.querySelector(".delete")
// 2.监听delete的点击
deleteEl.onclick = function() {
topBar.style.height = 0
// setTimeout(function() {
// topBar.remove()
// }, 300)
}
// 3.监听过渡动画结束
topBar.ontransitionend = function() {
topBar.remove()
}
script>
body>
html>
3.侧边栏展示
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>Documenttitle>
<style>
.tool-bar {
position: fixed;
top: 30%;
right: 0;
display: flex;
flex-direction: column;
align-items: center;
width: 35px;
}
.item {
position: relative;
width: 35px;
height: 35px;
margin-bottom: 1px;
background-color: #7a6e6e;
border-radius: 3px 0 0 3px;
}
.icon {
display: inline-block;
width: 100%;
height: 100%;
cursor: pointer;
background-image: url(./img/toolbars.png);
}
/* .icon01 {
background-position: -48px 0;
}
.icon02 {
background-position: -48px -50px;
}
.icon03 {
background-position: -48px -100px;
}
.icon04 {
background-position: -48px -150px;
} */
.name {
position: absolute;
z-index: -1;
right: 35px;
/* left: -62px; */
top: 0;
width: 0;
height: 35px;
line-height: 35px;
color: #fff;
text-align: center;
font-size: 12px;
background-color: #7a6e6e;
cursor: pointer;
border-radius: 3px 0 0 3px;
transition: width .2s ease;
}
.item:hover,
.item:hover .name {
background-color: #cd1926;
}
style>
head>
<body>
<div class="tool-bar">
<div class="item">
<i class="icon icon01">i>
<div class="name">购物车div>
div>
<div class="item">
<i class="icon icon02">i>
<div class="name">收藏div>
div>
<div class="item">
<i class="icon icon03">i>
<div class="name">限时活动div>
div>
<div class="item">
<i class="icon icon04">i>
<div class="name">大礼包div>
div>
div>
<script>
// 1.动态给icon设置backgroundPosition
var iconEls = document.querySelectorAll(".icon")
for (var i = 0; i < iconEls.length; i++) {
var iconEl = iconEls[i]
iconEl.style.backgroundPosition = `-48px -${50*i}px`
}
// 2.实现鼠标进入动画
// 方案一: mouseenter(不能使用事件委托)
var itemEls = document.querySelectorAll(".item")
for (var itemEl of itemEls) {
itemEl.onmouseenter = function() {
var nameEl = this.children[1]
nameEl.style.width = "62px"
}
itemEl.onmouseleave = function() {
var nameEl = this.children[1]
nameEl.style.width = "0"
}
}
// 方案二: mouseover(使用事件委托)
// var toolbarEl = document.querySelector(".tool-bar")
// toolbarEl.onmouseover = function(event) {
// handleMouseEvent(event, 62)
// }
// toolbarEl.onmouseout = function(event) {
// handleMouseEvent(event, 0)
// }
// function handleMouseEvent(event, width) {
// if (event.target !== toolbarEl) {
// // var itemEl = event.target.classList.contains("item") ? event.target: event.target.parentElement
// // 1.获取唯一的item
// var itemEl = null
// if (event.target.classList.contains("item")) {
// itemEl = event.target
// } else {
// itemEl = event.target.parentElement
// }
// // 2.根据item获取nameElement
// var nameEl = itemEl.children[1]
// // 3.设置宽度
// nameEl.style.width = `${width}px`
// }
// }
script>
body>
html>
4.登录框
DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Documenttitle>
<link rel="stylesheet" href="./css/iconfont.css">
<style>
body,input {
margin: 0;
padding: 0;
outline: none;
}
.container {
text-align: center;
}
.pannel {
display: inline-block;
padding: 30px;
width: 300px;
/* border-radius: 10px; */
/* border: 2px solid #ccc; */
}
.pannel .form-item {
display: flex;
width: 100%;
margin-bottom: 15px;
border: 1px solid #ccc;
}
.pannel .form-item .icon {
width: 40px;
height: 40px;
box-sizing: border-box;
border-right: 1px solid #ccc;
background-color: #eee;
vertical-align: bottom;
color: #ccc;
}
.pannel .form-item .icon.icon-account {
font-size: 24px;
line-height: 40px;
}
.pannel .form-item .icon.icon-password {
line-height: 40px;
font-size: 18px;
}
.pannel .form-item input {
padding-left: 10px;
height: 40px;
flex: 1;
box-sizing: border-box;
border-style: none;
}
.pannel .form-item i {
width: 20px;
margin: 0 3px;
font-style: normal;
color: #ccc;
line-height: 40px;
font-size: 20px;
}
button {
width: 100%;
background-color: rgb(233, 97, 99);
border-style: none;
padding: 5px 0;
font-size: 20px;
letter-spacing: 5px;
color: #fff;
}
style>
head>
<body>
<div class="container">
<div class="pannel">
<form action="/abc" method="post">
<h1>登录页面h1>
<div class="form-item">
<div class="icon iconfont icon-account">div>
<input type="text" name="username" id="username" placeholder="邮箱/用户名/登录手机">
<i class="remove-icon iconfont icon-delete">i>
div>
<div class="form-item">
<div class="icon iconfont icon-password">div>
<input type="password" name="password" id="password" placeholder="密码">
<i class="hidden-icon iconfont icon-no_eye">i>
<i class="remove-icon iconfont icon-delete">i>
div>
<button type="submit">登录button>
form>
div>
div>
<script>
var removeIconEls = document.querySelectorAll(".icon-delete");
removeIconEls.forEach(function (value) {
console.log(value);
value.addEventListener("click", function () {
console.log("当前元素：", this);
this.previousElementSibling.value = "";
})
})
script>
body>
html>
5.王者荣耀tabControl
DOCTYPE html>
<html lang="zh-CN">
<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>王者荣耀-main-newstitle>
<link rel="stylesheet" href="./css/reset.css">
<link rel="stylesheet" href="./css/common.css">
<style>
.main .section-content {
display: flex;
justify-content: space-between;
}
.main .section-content .left-content {
width: 872px;
height: 1000px;
}
.main .section-content .right-content {
width: 295px;
height: 500px;
}
style>
head>
<body>
<div class="main main_wrapper">
<div class="section-content">
<div class="left-content">
<div class="content-center">
<div class="section_header">
<div class="header_left">
<h3 class="title">内容中心h3>
div>
<div class="header_right" href="#">
<a class="more" href="#">更多a>
div>
div>
<div class="tab_control">
<div class="item active">精品栏目div>
<div class="line">div>
<div class="item">赛事精品div>
<div class="line">div>
<div class="item">英雄攻略div>
div>
div>
div>
div>
<script>
// 1.获取元素
var tabControl = document.querySelector(".tab_control")
// 2.监听鼠标进入(事件委托)
var activeLiEl = tabControl.querySelector(".active")
tabControl.onmouseover = function(event) {
// 1.拿到事件发生的对象
var itemEl = event.target
if (itemEl.classList.contains("item")) {
// 其他的取消active
// 1.for循环所有的item
// 2.querySelector(".active")
// 3.记录当前的active对应的item
activeLiEl.classList.remove("active")
// 当前进入的item变成active
itemEl.classList.add("active")
// 将最新的itemEl变成activeLiEl
activeLiEl = itemEl
}
}
script>
body>
html>
6.王者轮播图
DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Documenttitle>
<style>
body {
margin: 0;
padding: 0;
}
a {
text-decoration: none;
}
.box {
width: 604px;
height: 342px;
margin: 0 auto;
overflow: hidden;
}
.pic {
display: flex;
width: 100%;
height: 298px;
transition: all 300ms ease;
}
.pic .banner {
flex: 1;
}
.btn {
display: flex;
height: 44px;
background-color: #000;
}
.btn a {
flex: 1;
line-height: 44px;
font-size: 14px;
text-align: center;
color: #b1b2be;
}
.btn a.active,
.btn a:hover {
color: #f3c258;
background-color: rgba(255, 255, 255, 0.15);
}
style>
head>
<body>
<div class="box">
<div class="pic">
<a href="#" class="banner"><img src="./images/banner01.jpeg" alt="海诺设计理念">a>
<a href="#" class="banner"><img src="./images/banner02.jpeg" alt="季后赛宣传片">a>
<a href="#" class="banner"><img src="./images/banner03.jpeg" alt="KPL选秀招募">a>
<a href="#" class="banner"><img src="./images/banner04.jpeg" alt="荣耀大话王">a>
<a href="#" class="banner"><img src="./images/banner05.jpeg" alt="虔诚人物志">a>
div>
<div class="btn">
<a href="#" class="active">海诺设计理念a>
<a href="#">季后赛宣传片a>
<a href="#">KPL选秀招募a>
<a href="#">荣耀大话王a>
<a href="#">虔诚人物志a>
div>
div>
<script>
// 获取banner
var boxEl = document.querySelector(".box");
var picEl = document.querySelector(".pic");
var btnEl = document.querySelector(".btn");
var index = 0;
var activeBtn = document.querySelector(".active");
// 轮播图
var bannerTimer = exeBanner();
// 按钮鼠标切换
boxEl.onmouseover = function (event) {
// 暂停轮播
clearInterval(bannerTimer);
// 判断是否为按钮，不是则返回
if (event.target.parentElement !== btnEl ||
event.target === activeBtn) return;
//切换按钮激活
changeActive(event.target);
// 切换对应的banner
// 找到当前按钮的index
index = Array.from(btnEl.children).indexOf(activeBtn);
picEl.style.transform = `translate(-${604*index}px, 0)`;
}
boxEl.onmouseleave = function (event) {
// 开始轮播
bannerTimer = exeBanner();
}
// 改变激活按钮元素
function changeActive(activeEl) {
activeBtn.classList.remove("active");
activeBtn = activeEl;
activeBtn.classList.add("active");
}
// 执行轮播
function exeBanner(params) {
return setInterval(() => {
// banner图移动
picEl.style.transform = `translate(-${604*index}px, 0)`;
// 按钮切换
changeActive(btnEl.children[index]);
index++;
if (index === picEl.children.length) {
index = 0;
}
}, 3000);
}
script>
body>
html>
原版
DOCTYPE html>
<html lang="zh">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Documenttitle>
<style>
body {
margin: 0;
padding: 0;
}
a {
text-decoration: none;
}
.box {
width: 604px;
height: 342px;
margin: 0 auto;
overflow: hidden;
}
.pic {
display: flex;
position: relative;
width: 100%;
height: 298px;
}
.pic .banner {
position: absolute;
flex: 1;
/* transition: all 2000ms ease; */
}
.btn {
display: flex;
height: 44px;
background-color: #000;
}
.btn a {
flex: 1;
line-height: 44px;
font-size: 14px;
text-align: center;
color: #b1b2be;
}
.btn a.active,
.btn a:hover {
color: #f3c258;
background-color: rgba(255, 255, 255, 0.15);
}
style>
head>
<body>
<div class="box">
<div class="pic">
<a href="#" class="banner"><img src="./images/banner01.jpeg" alt="海诺设计理念">a>
<a href="#" class="banner"><img src="./images/banner02.jpeg" alt="季后赛宣传片">a>
<a href="#" class="banner"><img src="./images/banner03.jpeg" alt="KPL选秀招募">a>
<a href="#" class="banner"><img src="./images/banner04.jpeg" alt="荣耀大话王">a>
<a href="#" class="banner"><img src="./images/banner05.jpeg" alt="虔诚人物志">a>
div>
<div class="btn">
<a href="#" class="active">海诺设计理念a>
<a href="#">季后赛宣传片a>
<a href="#">KPL选秀招募a>
<a href="#">荣耀大话王a>
<a href="#">虔诚人物志a>
div>
div>
<script>
// 获取banner
var boxEl = document.querySelector(".box");
var picEl = document.querySelector(".pic");
var btnEl = document.querySelector(".btn");
var index = 0;
var lastIndex = index;
var activeBtn = document.querySelector(".active");
// 轮播图
var bannerTimer = exeBanner();
// 按钮鼠标切换
boxEl.onmouseover = function (event) {
// 暂停轮播
clearInterval(bannerTimer);
// 判断是否为按钮，不是则返回
if (event.target.parentElement !== btnEl ||
event.target === activeBtn) return;
//切换按钮激活
changeActive(event.target);
// 切换对应的banner
// 找到当前按钮的index
lastIndex = index;
index = Array.from(btnEl.children).indexOf(activeBtn);
bannerMove();;
}
boxEl.onmouseleave = function (event) {
// 开始轮播
bannerTimer = exeBanner();
}
// 改变激活按钮元素
function changeActive(activeEl) {
activeBtn.classList.remove("active");
activeBtn = activeEl;
activeBtn.classList.add("active");
}
// 执行轮播
function exeBanner(params) {
return setInterval(() => {
// 切换轮播图
bannerMove();
// 切换按钮
changeActive(btnEl.children[index]);
lastIndex = index;
index++;
// 重置index
if (index === picEl.children.length) {
index = 0;
}
}, 3000);
}
// 轮播图移动
function bannerMove() {
// 给上一张和下一张添加动画
for (var i = 0; i < picEl.children.length; i++) {
if (i === lastIndex || i === index) {
picEl.children[i].style.transition = "all 300ms ease";
continue;
}
picEl.children[i].style.transition = "none";
}
// banner图移动
if (index > 0) {
for (var i = 0; i < index; i++) {
picEl.children[i].style.left = "-100%";
}
}
if (index === 0) {
for (var i = 1; i < picEl.children.length; i++) {
picEl.children[i].style.left = "100%";
}
}
picEl.children[index].style.left = "0%";
if (index < picEl.children.length - 1) {
for (var i = index+1; i < picEl.children.length; i++) {
picEl.children[i].style.left = "100%";
}
}
}
script>
body>
html>
7.书籍购物车
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>Documenttitle>
<style>
table {
border-collapse: collapse;
}
thead {
background-color: #f5f5f5;
}
th, td {
border: 1px solid #aaa;
padding: 8px 12px;
text-align: center;
}
style>
head>
<body>
<table>
<thead>
<tr>
<th>编号th>
<th>书籍名称th>
<th>出版日期th>
<th>价格th>
<th>购买数量th>
<th>操作th>
tr>
thead>
<tbody>
tbody>
table>
<h2 class="price">
总价格: ¥<span class="price-count">0span>
h2>
<script>
// 1.从服务器获取数据 ajax/fetch
var books = [
{
id: 1,
name: '《算法导论》',
date: '2006-09',
price: 85.00,
count: 3
},
{
id: 2,
name: '《UNIX编程艺术》',
date: '2006-02',
price: 59.00,
count: 2
},
{
id: 3,
name: '《编程珠玑》',
date: '2008-10',
price: 39.00,
count: 5
},
{
id: 4,
name: '《代码大全》',
date: '2006-03',
price: 128.00,
count: 8
}
]
// 2.对数据展示
// 到底通过html直接编写, 还是通过JavaScriptDOM操作创建元素
// 1> 对于固定的, 直接通过html编写(能通过html编写, 尽量通过html直接编写)
// 2> 对于哪些大量的数据, 有规律的数据, 可以通过JavaScript编写
var tbodyEl = document.querySelector("tbody")
// 2.2. 动态添加tr以及内部数据
for (var i = 0; i < books.length; i++) {
var trowEl = document.createElement("tr")
// 2.3. 放具体数据
var book = books[i]
var bookKeys = Object.keys(book)
for (var m = 0; m < bookKeys.length; m++) {
var key = bookKeys[m]
var value = book[key]
var tdEl = document.createElement("td")
if (key === "price") {
value = "¥" + value
}
tdEl.textContent = value
trowEl.append(tdEl)
}
// 2.4. 添加删除按钮
var deleteTdEl = document.createElement("td")
var deleteBtnEl = document.createElement("button")
deleteBtnEl.textContent = "删除"
deleteTdEl.append(deleteBtnEl)
trowEl.append(deleteTdEl)
// 2.5.监听删除按钮的点击
deleteBtnEl.onclick = function() {
// 1.删除对应的trow
var deleteTRowEl = this.parentElement.parentElement
var deleteTrIndex = deleteTRowEl.sectionRowIndex
deleteTRowEl.remove()
// 2.删除对应books中的数据
books.splice(deleteTrIndex, 1)
// 3.重新计算一次价格
calcTotalPrice()
}
tbodyEl.append(trowEl)
}
// 3.计算总价格
var priceCountEl = document.querySelector(".price-count")
calcTotalPrice()
// 封装计算价格的函数
function calcTotalPrice() {
var totalPrice = books.reduce(function(preValue, item) {
return preValue + item.count * item.price
}, 0)
priceCountEl.textContent = totalPrice
}
script>
body>
html>