css实现小三角效果

<!DOCTYPE html>

<html>

<head>

<meta charset="UTF-8">

<title>新闻标题实例</title>

<style type="text/css">

#demo{

width:100px;

height:100px;

border: 2px #000 solid;

background-color:#fff;

position:relative;

}

#demo:before, #demo:after{

width:0px;

height:0px;

border:transparent solid;

position:absolute;

left:100%;

content:""

}

/*注意content虽然没有值,但是必须得加上*/

#demo:before{

border-width:10px;

border-left-color: #000;

top:20px;

}

#demo:after{

/* border-width:8px; 是为了覆盖黑色的框。*/

border-width:8px;

border-left-color: #fff;

top:22px;

}

</style>

</head>

<body>

<div >

</div>

</body>

</html>