js实现展开关闭下拉菜单

实现一个下拉菜单 点击title展开关闭菜单项 点击菜单项 让title显示点击的菜单项内容

<div class="wrap">
        <div class="menu">
            <div class="title">A-SOUL</div>
            <ul class="list">
                <li>嘉然</li>
                <li>向晚</li>
                <li>乃琳</li>
                <li>贝拉</li>
                <li>珈乐</li>
            </ul>
        </div>
    </div>

        * {
            margin: 0;
            padding: 0;
            font: 30px / 90px "微软雅黑";
        }

        ul {
            list-style: none;
        }

        .wrap {
            width: 1000px;
            height: 1000px;
            position: absolute;
            left: 50%;
            top: 50%;
            margin-top: -500px;
            margin-left: -500px;
            background: aliceblue;
        }

        .menu {
            width: 330px;
            border-radius: 10px;
            overflow: hidden;
            margin-top: 285px;
            margin-left: 335px;
            background: #f87a75;
            box-shadow: 0 20px 50px rgba(248, 122, 117, .5);
        }

        .title {
            height: 90px;
            padding-left: 112px;
            box-sizing: border-box;
            color: #fff;
            position: relative;
        }

        .title::after {
            content: '';
            position: absolute;
            right: 36px;
            top: 41px;
            background: url(images/ar.png) no-repeat;
            width: 28px;
            height: 16px;
        }

        .list {
            width: 316px;
            padding-left: 7px;
            padding-bottom: 5px;
            /* display: none; */
        }

        .list li {
            height: 90px;
            margin-bottom: 2px;
            background: #fee4e3;
            border-radius: 20px;
            padding-left: 112px;
            box-sizing: border-box;
            background-position: 23px 24px;
            background-repeat: no-repeat;

        }

        .list li:hover {
            background-color: #fff;
            box-shadow: 0 0 50px rgba(248, 122, 117, 0.93);
            position: relative;
        }

        .list li:nth-of-type(1) {
            background: #fee4e3 url(images/rr.png) no-repeat 30px center/45px 45px;
        }
        
        .list li:nth-of-type(2) {
            background: #fee4e3 url(images/向晚.png) no-repeat 30px center/45px 45px;
        }
        
        .list li:nth-of-type(3) {
            background: #fee4e3 url(images/乃琳.png) no-repeat 30px center/45px 45px;
        }
        
        .list li:nth-of-type(4) {
            background: #fee4e3 url(images/贝拉.png) no-repeat 30px center/45px 45px;
        }
        
        .list li:nth-of-type(5) {
            background: #fee4e3 url(images/珈乐.png) no-repeat 30px center/45px 45px;
        }
    </style>

var menu = document.querySelector('.menu')
        var title = document.querySelector('.title')
        var ul = document.querySelector('.list')
        var li = document.querySelectorAll('li')
        var flag = true

        title.onclick = function () {
            if (flag) {
                ul.style.display = 'none'
                // flag = false
            } else {
                ul.style.display = 'block'
                // flag = true
                if (title.innerHTML != 'A-SOUL') {
                    title.innerHTML = 'A-SOUL'
                }
            }
            flag = !flag
        }
        
for (let i = 0; i < li.length; i++) {
            li[i].onclick = function () {
                title.innerHTML = li[i].innerHTML
                ul.style.display = 'none'
                flag = false
            }
        }

这里的for循环 新手小伙伴们用var声明i的话可能会出现问题
可以看看另一篇文章
juejin.cn/post/706521…