三角的做法
Paste_Image.png
<!DOCTYPE html>
<html>
<head>
<title>Bootstrap</title>
<meta charset="utf-8">
<mata http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width,initial-scale=1">
<link rel="stylesheet" href="bootstrap/css/bootstrap.min.css">
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<script src="//cdn.bootcss.com/html5shiv/3.7.2/html5shiv.min.js"></script>
<script src="//cdn.bootcss.com/respond.js/1.4.2/respond.min.js"></script>
<![endif]-->
<style>
div {
width: 300px;
height: 40px;
border: 1px solid #5c5c5c;
margin: 100px auto;
position: relative;
}
div:after {
content: '';
width: 12px;
height: 12px;
display: block;
border-right: #5c5c5c solid 2px;
border-bottom: #5c5c5c solid 2px;
position: absolute;
top: 50%;
right: 12px;
transform: translateY(-50%) rotate(45deg);
}
div:hover {
border: 1px solid #009;
}
div:hover:after {
border-right: #009 solid 2px;
border-bottom: #009 solid 2px;
}
</style>
</head>
<body style="padding:50px;background-color:#ccc">
<div class="container" style="padding:30px;background-color:#fff;">
</div>
</body>
</html>
<!-- <script src="//cdn.bootcss.com/jquery/1.11.3/jquery.min.js"></script> -->
<script src="bootstrap/js/jquery.min.js"></script>
<script src="bootstrap/js/bootstrap.min.js"></script>
