1.div固定宽高
如果想要写一个居中于整个页面的,比如弹框呀,loading图等
html
<div class="loading></div>"
css
.loading{
width:100px;
height: 100px;
background-color:red;
position:absolute;
left:0;
top:0;
bottom:0;
right:0;
margin:auto;
}
如果是基于某个div中的
html
<div class="wrapper">
<div class="loading"></div>
</div>
css
在wrapper上增加position:relative;
.wrapper{
width:200px;
height: 200px;
background-color: green;
position:relative;
}
.circle{
width:100px;
height: 100px;
background-color:red;
position:absolute;
left:0;
top:0;
bottom:0;
right:0;
margin:auto;
}
复制代码
2.外部容器固定宽高
html
<div class="out">
<div class="inner"></div>
</div>
css
.out{
width: 500px;
height: 500px;
display:flex;
justify-content: center;
align-items: center;
}
.inner{width: 200px;height: 200px;}
复制代码
-
利用宽高的一半来实现居中
html
<div class="wrap center"> <div class="center2"></div> </div> 复制代码
css
.wrap { width: 100px; height: 100px; background-color: red; position: relative; } .center2 { width: 50px; height: 50px; background-color: green; position: absolute; left: 50%; top: 50%; margin-left: -25px; margin-top: -25px; //以上两行也可以改成transform的写法: transform: translateX(-50%) translateY(-50%); } 复制代码