<div class="container">
<div class="inner">
</div>
</div>
1.margin负值
.container {
width: 400px;
height: 400px;
border: 2px solid #111;
position: relative;
}
.inner {
width: 200px;
height: 200px;
background-color: #666;
position: absolute;
top: 50%;
left: 50%;
margin-top: -50px;
margin-left: -100px;
}
2.transform
.container {
width: 400px;
height: 400px;
border: 2px solid #111;
position: relative;
}
.inner {
width: 200px;
height: 200px;
background-color: #666;
position: absolute;
top: 50%;
left: 50%;
transform: translate(-50%,-50%);
}
3.margin: auto;
.container {
width: 400px;
height: 400px;
position: relative;
border: 1px solid #111;
}
.inner {
position: absolute;
background-color: #666;
width: 200px;
height: 200px;
margin: auto;
top: 0;
left: 0;
right: 0;
bottom: 0;
}
4.display: table-cell; vertical-align: middle; + margin: 0 auto;
.container {
width: 400px;
height: 400px;
border: 3px solid #111;
display: table-cell;
vertical-align: middle;
}
.inner {
width: 200px;
height: 200px;
margin: 0 auto;
background-color: #666;
}
5.display: table-cell; vertical-align: middle; text-align: center;+ display: inline-block;
.container {
width: 400px;
height: 400px;
border: 3px solid #111;
display: table-cell;
vertical-align: middle;
text-align: center;
}
.inner {
width: 200px;
height: 200px;
display: inline-block;
background-color: #666;
}
- display: flex;
.container {
width: 400px;
height: 400px;
border: 3px solid #111;
display: flex;
align-items: center;
justify-content: center;
}
.inner {
width: 200px;
height: 200px;
background-color: #666;
}