html - 如何在下拉菜单中使用 CSS 过渡属性

Question

我希望使用 transition 属性将鼠标悬停在上方时，下拉菜单的内容会在 0.3 秒内淡入淡出。将鼠标悬停在选项卡上时，它可以正常工作。

li.dropdown {
  display: inline-block;
}
.dropdown-content {
  display: none;
  position: absolute;
  background-color: #f9f9f9;
  min-width: 160px;
  box-shadow: 0px 8px 16px 0px rgba(0, 0, 0, 0.2);
}
.dropdown-content a {
  color: black;
  padding: 12px 16px;
  text-decoration: none;
  display: block;
  text-align: left;
}
.dropdown-content a:hover {
  background-color: #f1f1f1
}
.dropdown:hover .dropdown-content {
  display: block;
}

<li class="dropdown">
  <a href="#" class="dropbtn">Dropdown</a>
  <div class="dropdown-content">
    <a href="#">Link 1</a>
    <a href="#">Link 2</a>
    <a href="#">Link 3</a>
  </div>
</li>

Answer 1

试试这个，首先将 opacity:0 设置为您的下拉项并使用 transition 并且当您要将鼠标悬停在 block 上时 opacity:0 block 应该是 opacity:1

li.dropdown {
  display: inline-block;
}
.dropdown-content {
  opacity: 0;
  transition: opacity .3s ease-in-out;
  position: absolute;
  background-color: #f9f9f9;
  min-width: 160px;
  box-shadow: 0px 8px 16px 0px rgba(0, 0, 0, 0.2);
}
.dropdown-content a {
  color: black;
  padding: 12px 16px;
  text-decoration: none;
  display: block;
  text-align: left;
}
.dropdown-content a:hover {
  background-color: #f1f1f1
}
.dropdown:hover .dropdown-content {
    opacity: 1;
}

<li class="dropdown">
  <a href="#" class="dropbtn">Dropdown</a>
  <div class="dropdown-content">
    <a href="#">Link 1</a>
    <a href="#">Link 2</a>
    <a href="#">Link 3</a>
  </div>
</li>