class tab {
constructor(id) {
this.main = document.querySelector(id);
this.lis = this.main.querySelectorAll("li");
this.sets = document.querySelectorAll("section");
this.init();
}
init() {
for (let i = 0; i < this.lis.length; i++) {
this.lis[i].index = i;
this.lis[i].addEventListener("click", function () {
console.log(this.index);
console.log(this);
});
}
}
new tab("#tab");
```html
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>面向对象 Tabtitle>
<link rel="stylesheet" href="index.css">
head>
<body>
<main>
<h4>
Js 面向对象 动态添加标签页
h4>
<div class="tabsbox" id="tab">
<nav class="fisrstnav">
<ul>
<li class="liactive"><span>测试1span><span class="iconfont icon-guanbi">span>li>
<li><span>测试2span><span class="iconfont icon-guanbi">span>li>
<li><span>测试3span><span class="iconfont icon-guanbi">span>li>
ul>
<div class="tabadd">
<span>+span>
div>
nav>
<div class="tabscon">
<section class="conactive">测试1section>
<section>测试2section>
<section>测试3section>
div>
div>
main>
<script src="index.js">script>
body>
html>
```css
@font-face {font-family: "iconfont";
src: url('./iconfont/iconfont.eot?t=1553960438096'); /* IE9 */
src: url('./iconfont/iconfont.eot?t=1553960438096#iefix') format('embedded-opentype'), /* IE6-IE8 */
url('data:application/x-font-woff2;charset=utf-8;base64,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') format('woff2'),
url('./iconfont/iconfont.woff?t=1553960438096') format('woff'),
url('./iconfont/iconfont.ttf?t=1553960438096') format('truetype'), /* chrome, firefox, opera, Safari, Android, iOS 4.2+ */
url('./iconfont/iconfont.svg?t=1553960438096#iconfont') format('svg'); /* iOS 4.1- */
}
.iconfont {
font-family: "iconfont" !important;
font-size: 16px;
font-style: normal;
-webkit-font-smoothing: antialiased;
-moz-osx-font-smoothing: grayscale;
}
.icon-guanbi:before {
content: "\e676";
}
* {
margin: 0;
padding: 0;
}
ul li {
list-style: none;
}
main {
width: 960px;
height: 500px;
border-radius: 10px;
margin: 50px auto;
}
main h4 {
height: 100px;
line-height: 100px;
text-align: center;
}
.tabsbox {
width: 900px;
margin: 0 auto;
height: 400px;
border: 1px solid lightsalmon;
position: relative;
}
nav ul {
overflow: hidden;
}
nav ul li {
float: left;
width: 100px;
height: 50px;
line-height: 50px;
text-align: center;
border-right: 1px solid #ccc;
position: relative;
}
nav ul li.liactive {
border-bottom: 2px solid #fff;
z-index: 9;
}
#tab input {
width: 80%;
height: 60%;
}
nav ul li span:last-child {
position: absolute;
user-select: none;
font-size: 12px;
top: -18px;
right: 0;
display: inline-block;
height: 20px;
}
.tabadd {
position: absolute;
/* width: 100px; */
top: 0;
right: 0;
}
.tabadd span {
display: block;
width: 20px;
height: 20px;
line-height: 20px;
text-align: center;
border: 1px solid #ccc;
float: right;
margin: 10px;
user-select: none;
}
.tabscon {
width: 100%;
height: 300px;
position: absolute;
padding: 30px;
top: 50px;
left: 0px;
box-sizing: border-box;
border-top: 1px solid #ccc;
}
.tabscon section,
.tabscon section.conactive {
display: none;
width: 100%;
height: 100%;
}
.tabscon section.conactive {
display: block;
}
因为箭头函数没有this，自然也无法获取到this 下的 index，你可以在控制台打印一下，箭头函数本身没有this，他的this是上一层作用域的this