html5页面增强元素

<figure>
        <img src="images/1.jpg" alt="图片">
        <img src="images/2.jpg" alt="图片">
        <img src="images/3.jpg" alt="图片">
        <figcaption>图片</figcaption>
    </figure>

   <script>
        function details_onclick(detail){
            var  p = document.getElementById("p");
            if(detail.open){
                p.style.visibility = "hidden";
            }else{
                p.style.visibility = "visible";
            }
        }

    </script>
    <details id="detail" onclick="details_onclick(this)">
        <summary>梦想</summary>
        <p id="p" style="visibility: hidden">希望有一天能够完成未曾放弃的梦想</p>
    </details>

<p>这是一个<mark>mark</mark>测试，结果</p>