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lromeraj
Asked: 2020-05-13 08:06:16 +0800 CST 2020-05-13 08:06:16 +0800 CST

Transition on a dropdown doesn't work

  • 772

I'm trying to add a transition to this dropdown:

HTML :

<div class="dropdown">
  <button class="dropbtn">Select</button>
    <div class="dropdown_content">
      <a>1</a> 
      <a>2</a>
      <a>3</a>
      <a>4</a> 
    </div>
</div>

css :

.dropdown {
    position: relative;
    display: inline-block;
    width: 150px;
}

.dropbtn {
    background: #fff;
    box-shadow: 0 0 10px rgba(0,0,0,0.5);
    border-radius: 10px;
    font-size: 20px;
    color: #888;
    border: none;
    padding: 10px 10px;
    width: 100%;
}

.dropdown_content {
    position: absolute;
    display: block;
    height: 0px;
    margin-top: -2px;
    background: #fff;
    width: 100%;
    border-radius: 0px 0px 10px 10px;
    box-shadow: 0 13px 15px rgba(0,0,0,0.5);
    max-height: 150px;
    overflow-y: scroll;
    overflow-x: hidden;
    transition: ease 0.5s;
}

.dropdown_content a {
    display: block;
    color: #555;
    padding: 10px 0px;
    transition: ease 0.2s;
    cursor: pointer;
}

.dropdown_content a:hover {
    background: #0092ED;
    color: #fff;
}

.dropdown_content::-webkit-scrollbar {
    display: none;
}

.dropdown:hover .dropdown_content {
    height: auto;
}

.dropdown:hover .dropbtn {
    border-radius: 10px 10px 0px 0px;
    background: #0092ED;
    color: #fff;
}

I know the browser can't calculate a transition from display: none;to display: block;but in this case I'm changing the height of the dropdown_contentand I don't understand why it's not working.

I also leave it in JS Fiddle to save the copy and paste.

I would appreciate any possible help

html

1 Answers

  1. Best Answer

    You have to use max-height instead of height and set a fixed height to max-height

    .dropdown {
    position: relative;
    display: inline-block;
    width: 150px;
}

.dropbtn {
    background: #fff;
    box-shadow: 0 0 10px rgba(0,0,0,0.5);
    border-radius: 10px;
    font-size: 20px;
    color: #888;
    border: none;
    padding: 10px 10px;
    width: 100%;
}

.dropdown_content {
    position: absolute;
    display: block;
    margin-top: -2px;
    background: #fff;
    width: 100%;
    border-radius: 0px 0px 10px 10px;
    box-shadow: 0 8px 15px rgba(0,0,0,0.5);
    max-height: 0;
    overflow-y: scroll;
    overflow-x: hidden;
    z-index: 1;
    transition: ease 0.5s;
}

.dropdown_content a {
    display: block;
    color: #555;
    padding: 10px 0px;
    transition: ease 0.2s;
    cursor: pointer;
}

.dropdown_content a:hover {
    background: #0092ED;
    color: #fff;
}

.dropdown_content::-webkit-scrollbar {
    display: none;
}

.dropdown:hover .dropdown_content {
    max-height: 500px;
}

.dropdown:hover .dropbtn {
    border-radius: 10px 10px 0px 0px;
    background: #0092ED;
    color: #fff;
}
    <div class="dropdown">
  <button class="dropbtn">Select</button>
    <div class="dropdown_content">
      <a>1</a> 
      <a>2</a>
      <a>3</a>
      <a>4</a> 
    </div>
</div>

    • 1