css, js 項目聯繫之網頁換膚

首先，該練習參考自：https://www.jianshu.com/p/2961d9c317a3

我就直接上代碼了（顏色可以自己調）。

HTML:

    <nav>
        <li><a href="#">獨秀不愛秀</a></li>
        <li><a href="#">獨秀不愛秀</a></li>
        <li><a href="#">獨秀不愛秀</a></li>
        <li><a href="#">獨秀不愛秀</a></li>
        <li><a href="#">獨秀不愛秀</a></li>
        <li><a href="#">獨秀不愛秀</a></li>
    </nav>
    <ul id="skin">
        <li id="red"></li>
        <li id="green" class="current"></li>
        <li id="blue"></li>
    </ul>

CSS:

        /* 公共部分 */
        * {
            margin: 0;
            padding: 0;
        }
        html, body {
            font-size: 16px;
            transition: all 1s;
        }
        ul, nav {
            list-style: none;
        }


        /* 網頁皮膚選擇模塊 */
        #skin {
            margin-left: 100px;
            margin-top: 100px;
        }
        #skin li {
            width: 50px;
            height: 50px;
            color: #fff;
            line-height: 50px;
            text-align: center;
            border-radius: 50%;
        }
        #skin li + li {
            margin-top: 10px;
        }
        #skin #red {
            background-color: red;
            border: 25px solid red;
        }
        #skin #green {
            background-color: #009688bd;
            border: 25px solid #009688bd;
        }
        #skin #blue {
            background-color: blue;
            border: 25px solid blue;
        }
        #skin li.current {
            background-color: #fff!important;
        }
        #skin li:hover, #skin li:focus {
            background-color: #fff!important;
        }

        /* nav 模塊 */
        nav {
            width: 700px;
            height: 50px;
            margin: 100px auto;
        }
        nav li {
            width: 100px;
            height: 50px;
            float: left;
            line-height: 50px;
            text-align: center;
            transition: all 1s;
　　　　　　　border: 1px solid #fff;
        }
        nav li + li {
            margin-left: 10px;
        }
        nav li a {
            color: #fff;
            text-decoration: none;
        }
        nav li a:hover, nav li a:focus {
            text-decoration: underline;
        }

green.css

body {
    background: #8bc34a;
}
nav li {
    background-color: #009688bd;
}

red.css

body {
    background: #9e9e9e5e;
}
nav li {
    background-color: #ff5722eb;
}

blue.css

body {
    background: #673ab7a6;
}
nav li {
    background-color: #03a9f4a3;
}

JavaScript:

　　　　　　window.onload = () => {
            // 獲取選擇皮膚按鈕
            const skinLi = document.getElementById('skin').querySelectorAll('li');
            // 獲取 link 標簽
            const cssLink = document.getElementById('link');

            for (let i = 0; i < skinLi.length; i++) {
                skinLi[i].addEventListener('click', () => {
                    // 當點擊每一個選擇的時候先去除掉所有選擇按鈕的 class
                    for (ele in skinLi) {
                        skinLi[ele].className = '';
                    }
                    skinLi[i].className = 'current';
                    cssLink.href = `css/${skinLi[i].id}.css`;
                });
            }
        };