简单的tap栏切换

效果图：

HTML部分

    <div class="tab">
        <div class="tab_top">
            <ul>
                <li class="current">水果</li>
                <li>家电</li>
                <li>书籍</li>
                <li>服装</li>
            </ul>
        </div>
        <div class="tab_bottom">
            <div class="item" style="display: block;">水果区域</div>
            <div class="item">家电区域</div>
            <div class="item">书籍区域</div>
            <div class="item">服装区域</div>
        </div>
    </div>

css部分

        *{
            margin: 0;
            padding: 0;
        }
        .tab{
            margin: 100px auto;
            width: 500px;
            height: 600px;
            /* border: 1px solid red; */
        }
        .tab_top{
            width: 100%;
            height: 30px;
            background-color: #ccc;
            border-bottom: 3px solid red;
        }
        li{
            list-style: none;
            float: left;
            width: 80px;
            height: 30px;
            line-height: 30px;
            margin: 0 auto;
            text-align: center;
            /* background-color: red; */
        }
        .tab_bottom{
            margin-top: 30px;
        }
        .current{
            color: #fff;
            background-color: red;
        }
        li:hover{
            color: darkred;
        }
        .item{
            display: none;
        }

js代码部分

    <script>
        var tabTop = document.querySelector('.tab_top')
        var lis = document.querySelectorAll('li')
        var items = document.querySelectorAll('.item')
        for (var i = 0; i < lis.length; i++){
            lis[i].setAttribute('index',i)
            lis[i].onclick = function () {
                for (var i = 0; i < lis.length; i++) {
                    lis[i].className = ''
                }
                this.className = 'current'
                var index = this.getAttribute('index')
                for (var i = 0; i < items.length; i++){
                    items[i].style.display = 'none'
                }
                items[index].style.display = 'block'
            }
        }
    </script>