如何在页面加载时保持手风琴面板打开，但之后保持其可折叠性？

Question

对于我的手风琴菜单，我很难弄清楚如何在浏览器加载时让我的手风琴面板保持打开状态。我试过删除 overflow:hidden;对于面板，但我运行出错了。我希望能够在浏览器加载时打开我的面板，但之后让用户 open/close 链接。

HTML

<div class="sideMenu">
 <div class="logo">TS<div>
 <div class="smallSpacer"></div>

  <div class="accordion">code</div>
   <div class="panel">
    <p>uhn redesign </p>
    <p>180 websites </p>
 </div>

 <div class="bigSpacer"></div>

 <div class="accordion">design</div>
   <div class="panel">
    <p>gigloo </p>
    <p>space is the place</p>
    <p>tyler the creator </p>
    <p>nike concepts</p>
    <p>portraits/fashion</p>
 </div>

 <div class="bigSpacer"></div>

<div class="accordion">personal</div>
   <div class="panel">
    <p>product</p>
    <p>animations</p>
    <p>comics</p>

  </div>
</div>

CSS

body{
font-family: 'Roboto Mono', monospace;
}
.sideMenu{
 background-color:black;
width:250px;
height:100%;
position:fixed;
margin:20px;
text-align:center;
 }
.logo{
 color:white;
}

.smallSpacer{
 margin-bottom:15px;
}

.bigSpacer{
margin-bottom:20px;
}
.accordion {
color: white;
 cursor: pointer;
transition: 0.4s;
font-weight:500;
}

.active, .accordion:hover {

}

.panel {
font-weight:300;
 max-height: 0;
overflow: hidden;
transition: max-height 0.1s ease-out;
}

JAVASCRIPT

var acc = document.getElementsByClassName("accordion");
var i;

for (i = 0; i < acc.length; i++) {
 acc[i].addEventListener("click", function() {
this.classList.toggle("active");
var panel = this.nextElementSibling;
if (panel.style.maxHeight) {
  panel.style.maxHeight = null;
} else {
  panel.style.maxHeight = panel.scrollHeight + "px";
 }
 });
}

这是我的代码笔。 https://codepen.io/taniasharma98/pen/KKwQXBK

Answer 1

这是我的解决方案：

var acc = document.getElementsByClassName("accordion");
var i;

for (i = 0; i < acc.length; i++) {
//this is where magic happens
  if(i==0){
    acc[0].classList.toggle("active");
    var panel = acc[0].nextElementSibling;
    if (panel.style.maxHeight) {
      panel.style.maxHeight = null;
    } else {
      panel.style.maxHeight = panel.scrollHeight + "px";
    }
  }  

  acc[i].addEventListener("click", function() {
    this.classList.toggle("active");
    var panel = this.nextElementSibling;
    if (panel.style.maxHeight) {
      panel.style.maxHeight = null;
    } else {
      panel.style.maxHeight = panel.scrollHeight + "px";
    }
  });
}

如您所见，我所做的只是展开第一个元素的手风琴。我已经复制并粘贴了事件侦听器将执行的相同代码，而是在启动时直接将其附加到第一个元素。这也有助于保持可折叠性，因为已添加事件侦听器，而不管其他代码如何。

希望对您有所帮助！

如何在页面加载时保持手风琴面板打开，但之后保持其可折叠性？

How can I keep my accordion panels open when the page loads, but maintain its collapsibility afterwards?

html

javascript

css

accordion