<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
<style type="text/css">
*{
margin: 0;
padding: 0;
}
.wrapper{
margin: 100px;
border: 1px solid black;
width: 1000px;
height: 100px;
line-height: 100px;
text-align: center;
background: #f2f2f2;
}
.line{
display: inline-block;
width: 300px;
border-top: 1px dashed blue;
border-bottom: 1px dashed blue;
vertical-align: middle;
}
</style>
</head>
<body>
<div class="wrapper">
<span class="line"></span>
<span class="content">我是有底线的</span>
<span class="line"></span>
</div>
</body>
</html>
注意:利用span标签的border。