<style>
.pic_box{width:300px; height:300px; background-color:#beceeb; font-size:0; *font-size:200px; text-align:center;}
.pic_box img{vertical-align:middle;}
.pic_box::after{
content:'center';
display:inline-block;
width:0;
height:100%;
vertical-align:middle;
overflow:hidden;
} </style> <div class="pic_box">
<img src="http://i.santelvxing.com/upload/2016/ouc8qxay7-uystiw75ku-125148768.jpg" />
</div>
css div 实现三角形
<style>
.left{
float: left;
}
.mlr-20{
margin-left:20px;
margin-right:20px;
}
.triangle{
width: 0;
height: 0;
border: 20px solid #fff;
}
.triangle-down{
border-color: #209E6B transparent transparent transparent;
}
.triangle-right{
border-color: transparent transparent transparent #209E6B;
}
.triangle-special{
border-color: #209E6B #209E6B transparent #209E6B;
}
</style> <body>
<div class="triangle triangle-down left mlr-20"> </div>
<div class="triangle triangle-right left mlr-20"> </div>
<div class="triangle triangle-special left mlr-20"> </div>
</body>
CSS 伪类实现左上角标签
<style type="text/css">
.ui-cover-tip{
position: relative;
width: 200px;
height: 200px;
margin:0 auto;
border: solid 1px grey;
}
.ui-cover-tip:before{
content:'';
position: absolute;
display:block;
width: 0;
height: 0;
border-top: 60px solid #3399FF;
border-right: 60px solid transparent;
z-index: 2;
}
.ui-cover-tip:after{
content:'热门';
position: absolute;
top: 0px;
left: 0px;
width: 50px;
height: 30px;
transform: rotate(-45deg);
display: inline-block;
color:#fff;
z-index: 3
}
</style> <body>
<div class="ui-cover-tip"><div>
</body>
![在使用document.getElementById('xxx').files[0]时，关于计算图片大小](https://www.kunjuke.com/file/css/thumb/10.jpg/280-180.jpg)
