<div id="main">    <div class="demo">        <div class="bars">            <span id="bar">55</span>        </div>        <div class="bars">            <span id="bar2">75</span>        </div>        <div class="bars">            <span id="bar3">25</span>        </div>        <div class="bars">            <span id="bar4">45</span>            <p><button id="load">加載新數據</button> <button id="get">獲取數據</button></p>        </div>    </div></div>