如何用原生js截取所有li的文本内容并代替原本的内容

Question

比如 <ul>    <li>aaaaaaaaaaaaaaaaa</li>    <li>aaaaaaaaaaaaaaaaa</li>    <li>aaaaaaaaaaaaaaaaa</li>    <li>aaaaaaaaaaaaaaaaa</li>    <li>aaaaaaaaaaaaaaaaa</li> </ul> 如果li的长度大于5 则显示 <ul>    <li>aaaaa...</li>    <li>aaaaa...</li>    <li>aaaaa...</li>    <li>aaaaa...</li>    <li>aaaaa...</li> </ul>