<!doctype html> <html lang="en"> <head> <meta charset="utf-8"> <title>title</title> </head> <body> <ul> <li class="current">我是第1个li</li> <li>我是第2个li</li> <li>我是第3个li</li> <li>我是第4个li</li> <li>我是第5个li</li> <li>我是第6个li</li> <li>我是第7个li</li> <li>我是第8个li</li> </ul> </body> </html>
<style> *{ margin: 0; padding: 0; } ul{ list-style: none; margin: 100px auto; width: 300px; height: 400px; border: 1px solid #000; } ul>li{ font-size: 30px; font-weight: bold; margin-bottom: 10px; cursor: default; } .current{ background-color: brown; } </style>
<script> /* // es6之后的写法 let items = document.queryselectorall("li"); let previousindex = 0; for (let i = 0; i < items.length; i++) { // let currentitem = items[i]; items[i].onclick = function () { items[previousindex].classname = ""; this.classname = "current"; previousindex = i; // console.log(previousindex); }; } */ // es6之前的写法 var items = document.queryselectorall("li"); var previousindex = 0; for (var i = 0; i < items.length; i++) { (function (index) { items[index].onclick = function () { items[previousindex].classname = ""; this.classname = "current"; previousindex = index; }; })(i); } </script>
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