提示信息的设计
提示信息的类：
.alert:提示信息类
.alert alert-danger:
.alert alert-error:
.alert alert-success:
.alert alert-info:
.alert alert-block:
.alert alert-heading:
提示信息按钮：
<a href='javascript:;' class='close' data-dismiss='alert'></a>
代码块：
<div class='container'>
<h2 class='page-header'>Bootstrap 提示信息</h2> <div class='alert alert-heading'>
<!--给这个提示框添加一个关闭按钮-->
<a href='javascipt:;' class='close' data-dismiss='alert'>关闭</a>
<h4>温馨提示:</h4>
Built at Twitter by @mdo and @fat, Bootstrap utilizes LESS CSS, is compiled via Node, and is managed through GitHub to help nerds do awesome stuff on the web.
</div>
</div>
如图：