bootstrap 在线地址：http://www.bootcss.com/
http://v3.bootcss.com/getting-started/#download 下载用于生产环境的bootstrap
最好是使用自己下载的，因为我试过可能由于我电脑本身问题不能用。
提供基本模板中我们可以看出：我们需要加载三项：
1：bootstrap.css文件
2:jquery.js文件
3：bootstrap.js文件
要注意：2，3步的顺序不能颠倒
我们可以采用上面的实例精选：
代码如下：
<!DOCTYPE html>
<html lang="zh-CN">
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1">
<!-- 上述3个meta标签*必须*放在最前面，任何其他内容都*必须*跟随其后！ -->
<meta name="description" content="">
<meta name="author" content="">
<title>Starter Template for Bootstrap</title>
<!-- Bootstrap core CSS -->
<link href="bootstrap-3.3.4/css/bootstrap.min.css" rel="stylesheet">
<!-- Custom styles for this template -->
<!-- Just for debugging purposes. Don't actually copy these 2 lines! -->
<!--[if lt IE 9]><script src="../../assets/js/ie8-responsive-file-warning.js"></script><![endif]-->
<!-- HTML5 shim and Respond.js for IE8 support of HTML5 elements and media queries -->
<!--[if lt IE 9]>
<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]-->
</head>
<body>
<nav class="navbar navbar-inverse navbar-fixed-top">
<div class="container">
<div class="navbar-header">
<button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#navbar" aria-expanded="false" aria-controls="navbar">
<span class="sr-only">Toggle navigation</span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
</button>
<a class="navbar-brand" href="#">Project name</a>
</div>
<div id="navbar" class="collapse navbar-collapse">
<ul class="nav navbar-nav">
<li class="active"><a href="#">Home</a></li>
<li><a href="#about">About</a></li>
<li><a href="#contact">Contact</a></li>
</ul>
</div><!--/.nav-collapse -->
</div>
</nav>
<div class="container">
<div class="starter-template">
<h1>Bootstrap starter template</h1>
<p class="lead">Use this document as a way to quickly start any new project.<br> All you get is this text and a mostly barebones HTML document.</p>
</div>
</div><!-- /.container -->
<!-- Bootstrap core JavaScript
================================================== -->
<!-- Placed at the end of the document so the pages load faster -->
<script src="jquery-1.9.0.main.js"></script>
<script src="bootstrap-3.3.4/js/bootstrap.min.js"></script>
<!-- IE10 viewport hack for Surface/desktop Windows 8 bug -->
</body>
</html>
请注意：最好是修改本地的css,js文件地址；