js特效列表可收缩

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Collapsible List</title>
    <style>
        .collapsible {
            background-color: #eee;
            color: #444;
            cursor: pointer;
            padding: 18px;
            width: 100%;
            border: none;
            text-align: left;
            outline: none;
            font-size: 15px;
        }

        .active, .collapsible:hover {
            background-color: #ccc;
        }

        .content {
            padding: 0 18px;
            display: none;
            overflow: hidden;
            background-color: #f1f1f1;
        }
    </style>
</head>
<body>

<h2>Collapsible List</h2>

<button class="collapsible">Section 1</button>
<div class="content">
  <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.</p>
</div>

<button class="collapsible">Section 2</button>
<div class="content">
  <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.</p>
</div>

<script>
    var coll = document.getElementsByClassName("collapsible");
    for (var i = 0; i < coll.length; i++) {
        coll[i].addEventListener("click", function() {
            this.classList.toggle("active");
            var content = this.nextElementSibling;
            if (content.style.display === "block") {
                content.style.display = "none";
            } else {
                content.style.display = "block";
            }
        });
    }
</script>

</body>
</html>