一般地,居中绝对定位元素,left:50%;top:50%;
再margin负值
或者通过transform
也可达到效果。
今天发现另一个技巧,利用,top,left,right,bottom取值0
,再magin:auto
,即可实现居中。
原因:
For absolutely positioned elements, the top, right, bottom,and left properties specify offsets from the edge of the element’s containing block (what the element is positioned relative to).The margin of the element is then positioned inside these offsets.
<div class='box>
<div class='jz'></div>
</div>
div.box{
position: relative;
height: 300px;
background: #989eaa;
}
div.fz{
width: 100px;
height: 100px;
background: #499682;
position: absolute;
top:0;
left: 0;
right: 0;
bottom: 0;
margin:auto;
}
注:子元素大的话,上下可居中,左右失效。