Class选择器

node2:/var/www/html/js#cat h16.html 
<div>
 <p class="description">I'm a paragraph</p>
 </div>
 <div>
   <h1 class="green"><Another title</h1>
    <a class="description">test</a>
   <p  class="description blue">I'm yet another paragraph</p>
 </div>
<div>
<a class='aaaaaaaaaa'>77777</a>
    <li class="description">test</li>
</div>
<script type="text/javascript" src="jquery-2.2.2.min.js"></script> 
<script type="text/javascript" src="h16.js"></script>


node2:/var/www/html/js#cat h16.js
 $('.description').css("background","#bbffaa")