学习使用bootstrap基本控件（table、form、button）

bootstrap为我们定义了简洁易用的样式，我们只需要很少的样式指定，就可以完成简约优雅的页面展示。
本篇主要介绍以下几个基本控件：
1. table
2. form
3. button

1. 表格（table）依旧使用<table><thead><tbody><tr><th><td>来表现表格。有如下的类来控制table的属性， table样式默认会占满父容器

 <div class="container">
 <div class="row">
  <div class="col-md-8 col-md-offset-2">
  <table class="table table-bordered table-striped table-hover">
  <tr>
  <th>标题一</th>
  <th>标题二</th>
  <th>标题三</th>
  </tr>
  <tr>
  <td>1</td>
  <td>2</td>
  <td>3</td>
  </tr>
  <tr>
  <td>4</td>
  <td>5</td>
  <td>6</td>
  </tr>
 </table>
  </div>
 </div>
 </div>

将任何.table包裹在.table-responsive中即可创建响应式表格，其会在小屏幕设备上（小于768px）水平滚动。当屏幕大768px宽度时，水平滚动条消失。

2. 表单form, 有如个几种样式定义

lable与控件要用form-group类型的div包起来，默认表单如下

 <div class="container">
 <form>
  <div class="form-group">
  <label for="exampleInputEmail1">Email address</label>
  <input type="email" class="form-control" id="exampleInputEmail1"
   placeholder="Enter email">
  </div>
  <div class="form-group">
  <label for="exampleInputPassword1">Password</label>
  <input type="password" class="form-control"
   id="exampleInputPassword1" placeholder="Password">
  </div>
  <div class="checkbox">
  <label> <input type="checkbox"> Check me out
  </label>
  </div>
  <button type="submit" class="btn btn-default">Submit</button>
 </form>
 </div>

内联表单，为label指定sr-only类别，可隐藏掉标签，但必须 不可省略lable.

 <div class="container">
 <form class="form-inline">
  <div class="form-group">
  <label for="exampleInputEmail1" class="sr-only">Email address</label>
  <input type="email" class="form-control" id="exampleInputEmail1"
   placeholder="Enter email">
  </div>
  <div class="form-group">
  <label for="exampleInputPassword1">Password</label>
  <input type="password" class="form-control"
   id="exampleInputPassword1" placeholder="Password">
  </div>
  <div class="checkbox">
  <label> <input type="checkbox"> Check me out
  </label>
  </div>
  <button type="submit" class="btn btn-default">Submit</button>
 </form>
 </div>

水平类型的表单，要为lable与标签组指定长度， 采用栅格系统的布局方式。 label右对齐，标签组左对齐。  

 <div class="container">
 <form class="form-horizontal">
  <div class="form-group">
   <label for="exampleInputEmail1" class="col-md-2 control-label">Email
   address</label>
  <div class="col-md-8">
   <input type="email" class="form-control" id="exampleInputEmail1"
   placeholder="Enter email">
  </div>
  </div>
  <div class="form-group" >
   <label for="exampleInputPassword1" class="col-md-2 control-label">Password</label>
  <div class="col-md-8">
   <input type="password" class="form-control"
   id="exampleInputPassword1" placeholder="Password">
  </div>
  </div>
  <div class="checkbox col-md-offset-2">
  <label> <input type="checkbox"> Check me out
  </label>
  </div>
  <button type="submit" class="btn btn-default col-md-offset-2">Submit</button>
 </form>
 </div>

form表单验证，bootstrap3支持表单的自定义验证。 加入req    uired表示表单必填，node.setCustomValidity可以设置表单的自定义验证

<div class="container">
 <form class="form-horizontal">
  <div class="form-group">
  <label for="exampleInputEmail1" class="col-md-2 control-label">Email
   address</label>
  <div class="col-md-8">
   <input type="email" class="form-control" id="exampleInputEmail1"
   placeholder="Enter email" required>
  </div>
  </div>
  <div class="form-group">
  <label for="password1" class="col-md-2 control-label">Password</label>
  <div class="col-md-8">
   <input type="password" class="form-control"
   id="password1" placeholder="Password" required onchange="checkPassword()">
  </div>
  </div>
<div class="form-group">
  <label for="password2" class="col-md-2 control-label" onchange="checkPassword()"> Password2</label>
  <div class="col-md-8">
   <input type="password" class="form-control"
   id="password2" placeholder="Password2" required>
  </div>
  </div>
  <div class="checkbox col-md-offset-2">
  <label> <input type="checkbox"> Check me out
  </label>
  </div>
  <button type="submit" class="btn btn-default col-md-offset-2">Submit</button>
 </form>
 </div>
 
 <script>
 function checkPassword() {
  var pwd1 = $("#password1").val();
  var pwd2 = $("#password2").val();
  if (pwd1 != pwd2) {
  document.getElementById("password1").setCustomValidity("两次输入的密码不一致");
  } else {
  document.getElementById("password1").setCustomValidity("");
  }
  
 }
 </script>

3. button的样式

使用.btn-lg、.btn-sm、.btn-xs可以获得不同尺寸的按钮， 给按钮添加.btn-block可以使其充满父节点100%的宽度，而且按钮也变为了块级（block）元素， <a>、<button>或<input>元素添加按钮class。 

 <div class="container">
 <button type="button" class="btn btn-default btn-block">Default</button>
 <button type="button" class="btn btn-primary btn-block">Primary</button>
 <button type="button" class="btn btn-success">Success</button>
 <button type="button" class="btn btn-info">Info</button>
 <button type="button" class="btn btn-warning">Warning</button>
 <button type="button" class="btn btn-danger">Danger</button>
 <button type="button" class="btn btn-link">链接</button>
 <a class="btn btn-default" href="#" role="button">Link</a>
 <button class="btn btn-default" type="submit">Button</button>
 <input class="btn btn-default" type="button" value="Input">
 <input class="btn btn-default" type="submit" value="Submit"&