行内元素
<div class="demo1">1111</div
.demo1 {
width: 100px;
height: 30px;
border: 1px solid #333;
}
line-height + text-align
.demo1 {
/* 水平居中 */
text-align: center;
/* 垂直居中: line-height = height */
line-height: 30px;
}
行内块状元素
line-height + vertical-align + text-align
vertical-align 只能应用在行内元素和单元格元素上。
<div class="demo1">
<img src="https://dss2.bdstatic.com/6Ot1bjeh1BF3odCf/it/u=1765461753,2420530801&fm=218&app=92&f=PNG?w=121&h=75&s=A7D53F6EC4F07F803ADE5F7D0300D07C">
</div>
.demo1 {
width: 500px;
height: 200px;
border: 1px solid #333;
/* 关键代码 */
text-align: center;
line-height: 200px;
}
img {
vertical-align: middle;
}
display: table/table-cell + vertical-align + text-align
<div class="demo1">
<div class="content">
<p>1111111</p>
<p>2222222</p>
</div>
</div>
.demo1 {
width: 500px;
height: 200px;
border: 1px solid #333;
/* 关键代码 */
display: table;
}
.content {
vertical-align: middle;
display: table-cell;
text-align: center;
}
块状元素
<div class="parent">
<div class="child"></div>
</div>
position + margin
.parent {
position: relative;
}
.child {
position: absolute;
top: 0;
right: 0;
bottom: 0;
left: 0;
margin: auto;
}
flex + margin
.parent {
display: flex;
/* 定义项目在主轴上如何对齐 */
justify-content: center;
/* 定义项目在交叉轴上如何对齐 */
align-items: center;
}
或者
.parent {
display:flex;
}
.child {
margin: auto;
}
grid
.parent {
display: grid;
}
.child {
justify-self: center;
align-self: center;
}
或者
.parent {
display:grid;
}
.child {
margin: auto;
}
transform + position
.parent {
position: relative;
}
.child {
position: absolute;
top: 50%;
left: 50%;
transform: translate(-50%, -50%);
}