<html lang="en" xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<title>web</title>
<link href="css/bootstrap.css" rel="stylesheet" type="text/css" />
<link href="css/bootstrap-responsive.css" rel="stylesheet" type="text/css" />
<link href="css/style.css" rel="stylesheet" type="text/css" />
<script type="text/javascript" src="js/bootstrap.js"></script>
<script type="text/javascript" src="js/bootstrap-carousel.js"></script>
<script type="text/javascript" src="js/bootstrap-dropdown.js"></script>
</head>
<body>
<div class="container">
<div class="row">
<div class="span4"></div>
<div class="span4"></div>
<div class="span4">
<div class="btn-toolbar" style="margin-top: 18px;">
<div class="btn-group">
<button class="btn btn-primary">动作</button>
<button class="btn btn-primary dropdown-toggle" data-toggle="dropdown"><span class="caret"></span></button>
<ul class="dropdown-menu dropup">
<li><a href="#">动作</a></li>
<li><a href="#">其他动作</a></li>
<li><a href="#">其他</a></li>
<li class="divider"></li>
<li><a href="#">被间隔的链接</a></li>
</ul>
</div>
</div>
</div>
代码,图片显示效果如上,为什么右边红色区域背景的高度跟左边背景颜色的高度不一般高呢?请多多指教