我想保持跟随手风琴的过渡效果

Question

我想使用按钮创建嵌套的手风琴，但是每当我尝试实现它时，它就只能第一次使用。

我仅在上面的示例中首先介绍了Asdf手风琴的工作原理，其余的均无效。

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";
    } 
  });
}

.accordion {
background-color: #f7f7f7;
color: #3985ff;
cursor: pointer;
padding: 15px;
width: 100%;
border: none;
text-align: left;
outline: none;
font-size: 18px;
transition: 0.2s;
text-decoration: underline;
}

.active, .accordion:hover {
background-color: #eee;
}
.accordion:after {
    content: '\002B';
    color: #777;
    font-weight: bold;
    float: right;
    margin-left: 5px;
}

.active:after {
    content: "\2212";
}
.panel {
padding: 0 18px;
background-color: white;
max-height: 0;
overflow: hidden;
transition: max-height 0.2s ease-out;
}

<button class="accordion">asdf</button>
<div class="panel">
	<p>&#160;</p>
	asdf
    <button class="accordion">asdf</button>
<div class="panel">
	<p>&#160;</p>
	asdf
</div>
</div>
<button class="accordion">qwer</button>
<div class="panel">
	<p>&#160;</p>
	asdf
</div>

我仅在上面的示例中首先介绍了Asdf手风琴的工作原理，其余的均无效。

Answer 1

问题在于单击元素时设置元素高度的方式。见下文。

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

for (var i = 0; i < acc.length; i++) {
  acc[i].addEventListener("click", function() {
    this.classList.toggle("active");
    var panel = this.nextElementSibling;
    panel.style.maxHeight = '100%';
  });
}

.accordion {
background-color: #f7f7f7;
color: #3985ff;
cursor: pointer;
padding: 15px;
width: 100%;
border: none;
text-align: left;
outline: none;
font-size: 18px;
transition: 0.2s;
text-decoration: underline;
}

.active, .accordion:hover {
background-color: #eee;
}
.accordion:after {
    content: '\002B';
    color: #777;
    font-weight: bold;
    float: right;
    margin-left: 5px;
}

.active:after {
    content: "\2212";
}
.panel {
padding: 0 18px;
background-color: white;
max-height: 0;
overflow: hidden;
transition: max-height 0.2s ease-out;
}

<button class="accordion">asdf</button>
<div class="panel">
	<p>&#160;</p>
	asdf
    <button class="accordion">asdf</button>
<div class="panel">
	<p>&#160;</p>
	asdf
</div>
</div>
<button class="accordion">qwer</button>
<div class="panel">
	<p>&#160;</p>
	asdf
</div>