一行可以实现省略号：
overflow: hidden
white-space: nowrap
text-overflow: ellipsis
案例<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Document</title>
<style>
.box {
width: 900px
background-color: #eee
border: 1px dashed #ccc
margin: 0 auto
}
.top {
height: 80px
}
.banner {
height: 120px
/*margin: 0 auto*/
margin: 5px auto
}
.main {
height: 500px
}
.footer {
height: 100px
/*margin: 0 auto
margin-top:5px*/
margin: 5px auto 0
}
</style>
</head>
<body>
<div class="top box">top</div>
<div class="banner box">banner</div>
<div class="main box"></div>
<div class="footer box"></div>
</body>
</html>
