SOURCE

class Tabs {
    constructor(id) {
        this.main = document.querySelector(id)
    }
    // 初始化
    init () {

    }
    // 点击切换
    taggleTab() {

    }
    // 添加选项
    addTab() {

    }
    // 删除选项
    removeTab() {

    }
}
const tabs = new Tabs('#tabs')
console.log(tabs)

<div id="tabs">
	<ul>
		<li class="active-lis">
            <span>选项卡1</span>
            <span>x</span>
        </li>
		<li>
            <span>选项卡2</span>
            <span>x</span>
        </li>
		<li>
            <span>选项卡3</span>
            <span>x</span>
        </li>
	</ul>
    <section class="active-sec">
        <span>选项卡1内容</span>
    </section>
    <section>
        <span>选项卡2内容</span>
    </section>
    <section>
        <span>选项卡2内容</span>
    </section>
</div>

.tabs {
    margin: 50px;
    border: 1px solid #999999
}
ul {
    display: block;
    list-style-type: none;
    padding-inline-start: 0;
    margin-block-end: 0;
    margin-block-start: 0;
    overflow: hidden
}
li {
    position: relative;
    display: block;
    float: left;
    width: 96px;
    height: 48px;
    line-height: 48px;
    border-right: 1px solid #999999;
    border-bottom: 1px solid #999999;
    text-align: center
}
li span:nth-child(2) {
    display: inline-block;
    position: absolute;
    right: 4px;
    top: -16px;
}
li.active-lis {
    border-bottom: none
}
section {
    padding: 16px;
    height: 100px
}