居中下拉按钮

Question

我是新手，刚学编程。我想我被困在了一件非常简单的事情上。如何使页面中的下拉按钮居中？这是 HTML 代码。

.dropbtn {
  background-color: #04AA6D;
  color: white;
  padding: 16px;
  font-size: 16px;
  border: none;
  min-width: 110px;
  font-weight: bold;
  vertical-align: middle;
}

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

.dropdown-content {
  display: none;
  position: center;
  background-color: #f1f1f1;
  min-width: 110px;
  box-shadow: 0px 8px 16px 0px rgba(0,0,0,0.2);
  z-index: 1;
  text-align: center;
}

.dropdown-content a {
  color: black;
  padding: 12px 16px;
  text-decoration: none;
  display: block;
}

.dropdown-content a:hover {background-color: #ddd;}

.dropdown:hover .dropdown-content {display: block;}

.dropdown:hover .dropbtn {background-color: #3e8e41;}

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

我没有为这个下拉按钮使用任何 CSS 或 JavaScript。

我是否也应该使用 CSS 和 JavaScript 来使此代码运行好？

请多指教

谢谢。

Answer 1

您可以将下拉的位置改为绝对位置，并设置左侧和顶部。

.dropdown {
  position: absolute;
  top: 50%;
  left: 50%;
  display: inline-block;
  transform: translate(-50%,-50%)
}

Answer 2

您可以使用：

body {
  display: flex;
  justify-content: center;
}

( 在现实世界的场景中，您将把它应用到容器元素而不是整个主体）

body {
  display: flex;
  justify-content: center;
}

.dropbtn {
  background-color: #04AA6D;
  color: white;
  padding: 16px;
  font-size: 16px;
  border: none;
  min-width: 110px;
  font-weight: bold;
  vertical-align: middle;
  margin: 0 auto;
}

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

.dropdown-content {
  display: none;
  position: center;
  background-color: #f1f1f1;
  min-width: 110px;
  box-shadow: 0px 8px 16px 0px rgba(0, 0, 0, 0.2);
  z-index: 1;
  text-align: center;
}

.dropdown-content a {
  color: black;
  padding: 12px 16px;
  text-decoration: none;
  display: block;
}

.dropdown-content a:hover {
  background-color: #ddd;
}

.dropdown:hover .dropdown-content {
  display: block;
}

.dropdown:hover .dropbtn {
  background-color: #3e8e41;
}

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

Answer 3

您也可以使用这个简单的方法来：

.dropdown {
  position: relative;
  display: inline-block;
  text-align: center;
  width: 100%;
}

Answer 4

.dropbtn {
  background-color: #04AA6D;
  color: white;
  padding: 16px;
  font-size: 16px;
  border: none;
  min-width: 110px;
  font-weight: bold;
  vertical-align: middle;
}

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

.dropdown-content {
  display: none;
  position: center;
  background-color: #f1f1f1;
  min-width: 110px;
  box-shadow: 0px 8px 16px 0px rgba(0,0,0,0.2);
  z-index: 1;
  text-align: center;
}

.dropdown-content a {
  color: black;
  padding: 12px 16px;
  text-decoration: none;
  display: block;
}

.dropdown-content a:hover {background-color: #ddd;}

.dropdown:hover .dropdown-content {display: block;}

.dropdown:hover .dropbtn {background-color: #3e8e41;}

.dropdown{
   display:flex;
   flex-direction:column;
   justify-content:center;
   align-items:center;
   border:solid 2px green;
   height:100vh;
   }

<!DOCTYPE html>
<html>



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

</html>

居中下拉按钮

Centering Drop Down Button

html

css

dropdownbox

dropdown