CSS实现垂直居中的几种方法小结

//html
<div class="middle">555</div>
 
//css
.middle{
  height: 50px;
  line-height: 50px;
  background: red;
}

//html
<div class="main">
   <div class="middle"></div>
</div>

//css
.main {
  width: 200px;
  height: 300px;
  line-height: 300px;
  background: #dddddd;
}
.middle{
  background: red;
  width: 200px;
  height: 50px;
  display: inline-block;//或者display: inline-table;
  vertical-align: middle;
}

//html
<div class="main">
  <div class="middle"></div>
</div>
  
//css
.main {
  width: 60px;
  height: 10%;
  background: #dddddd;
  position: relative;//父元素设为相对定位
}
.middle{
  position: absolute;//设为绝对定位
  top: 50%;//top值为50%
  margin-top: -25%;//设margin-top为元素高度的一半
  width: 60px;
  height: 50%;
  background: red;
}

//html
<div class="main">
  <div class="middle"></div>
</div>
  
//css
.main {
  width: 60px;
  height: 10%;
  background: #dddddd;
  position: relative;//父元素设为相对定位
}
.middle{
  width: 30%;
  height: 50%;
  position: absolute;//设为绝对定位
  top: 0;
  bottom: 0;//top、bottom设0即可，
  left: 0;//如果left、right也设为0则可实现水平垂直都居中
  right: 0;
  margin:auto;
  background: red;
}

//html
<div class="main">
  <div class="middle"></div>
</div>
 
//css
.main {
  width: 60px;
  height: 10%;
  background: #dddddd;
  display: flex;//设为flex
  justify-content: center;//水平居中
  align-items: center;//垂直居中
}
.middle{
  width: 30%;
  height: 50%;
  background: red;
}