js中获取某个类下的某个标签，提示错误？

Question

html结构为：<nav class="nav-class">    <ul class="ul-class">        <li class="li-class"><a class="a-class">链接1</a></li>        <li class="li-class"><a class="a-class">链接2</a></li>        <li class="li-class"><a class="a-class">链接3</a></li>        <li class="li-class"><a class="a-class">链接4</a></li>        <li class="li-class">            <a class="a-class">链接5</a>            <ul>                <li class="li-class"><a class="a-class">链接6</a></li>                <li class="li-class"><a class="a-class">链接7</a></li>            </ul>        </li>    </ul></nav>JS获取 nav-class 下的 a 标签：var urlLink = document.getElementsByClassName('nav-class').getElementsByTagName('a'), find = false;提示错误，这样的应该如何获取？谢谢

Answer 1

先给代码：

var urlLink = document.getElementsByClassName('nav-class').item(0).getElementsByTagName('a').item(0);

不管是Document还是Element对象，你调getElements~返回的就是个集合，所以你要想不这么麻烦，要不用id要不就上个querySelectorAll得了……