-第一种方法
<style type="text/css">
* {
margin: 0;
padding: 0;
}
html,body{
/* margin:0 auto; */
height: 100%;
}
.parent {
display: table;
margin: 0 auto;
position: absolute;
top:0;left:0;right:0;bottom: 0;
margin:auto;
}
.parent {
width: 50%;
height: 50%;
background: #808080;
}
.child {
display: table-cell;
}
.child {
vertical-align: middle;
text-align: center;
}
.child>span{
width:100px;
height:100px;
background: #DAA520;
}
</style>
</head>
<body>
<div class="parent">
<div class="child"><span></span></div>
</div>
</body>
