Bootstrap4 输入框组

我们可以使用 .input-group 类来向表单输入框中添加更多的样式，如图标、文本或者按钮。

使用 .input-group-prepend 类可以在输入框的的前面添加文本信息， .input-group-append 类添加在输入框的后面。

最后，我们还需要使用 .input-group-text 类来设置文本的样式。

Bootstrap4 输入框组

Bootstrap4 实例

<form>
  <div class="input-group mb-3">
    <div class="input-group-prepend">
      <span class="input-group-text">@</span>
    </div>
    <input type="text" class="form-control" placeholder="Username">
  </div>
 
  <div class="input-group mb-3">
    <input type="text" class="form-control" placeholder="Your Email">
    <div class="input-group-append">
      <span class="input-group-text">@runoob.com</span>
    </div>
  </div>
</form>

输入框大小

使用 .input-group-sm 类来设置小的输入框， .input-group-lg 类设置大的输入框：

Bootstrap4 实例

<form>
  <div class="input-group mb-3 input-group-sm">
     <div class="input-group-prepend">
       <span class="input-group-text">Small</span>
    </div>
    <input type="text" class="form-control">
  </div>
</form>
<form>
  <div class="input-group mb-3">
    <div class="input-group-prepend">
      <span class="input-group-text">Default</span>
    </div>
    <input type="text" class="form-control">
  </div>
</form>
<form>
  <div class="input-group mb-3 input-group-lg">
    <div class="input-group-prepend">
      <span class="input-group-text">Large</span>
    </div>
    <input type="text" class="form-control">
  </div>
</form>

多个输入框和文本

Bootstrap4 实例

<!-- 多个输入框 -->
<form>
  <div class="input-group mb-3">
    <div class="input-group-prepend">
      <span class="input-group-text">Person</span>
    </div>
    <input type="text" class="form-control" placeholder="First Name">
    <input type="text" class="form-control" placeholder="Last Name">
  </div>
</form>
 
<!-- 多个文本信息 -->
<form>
  <div class="input-group mb-3">
    <div class="input-group-prepend">
      <span class="input-group-text">One</span>
      <span class="input-group-text">Two</span>
      <span class="input-group-text">Three</span>
    </div>
    <input type="text" class="form-control">
  </div>
</form>

复选框与单选框

文本信息可以使用复选框与单选框替代：

Bootstrap4 输入框组

Bootstrap4 实例

<div class="input-group mb-3">
  <div class="input-group-prepend">
    <div class="input-group-text">
      <input type="checkbox"> 
    </div>
  </div>
  <input type="text" class="form-control" placeholder="RUNOOB">
</div>
 
<div class="input-group mb-3">
  <div class="input-group-prepend">
    <div class="input-group-text">
      <input type="radio"> 
    </div>
  </div>
  <input type="text" class="form-control" placeholder="GOOGLE">
</div>

输入框添加按钮组

Bootstrap4 实例

<div class="input-group mb-3">
  <div class="input-group-prepend">
    <button class="btn btn-outline-secondary" type="button">Basic Button</button> 
  </div>
  <input type="text" class="form-control" placeholder="Some text">
</div>
 
<div class="input-group mb-3">
  <input type="text" class="form-control" placeholder="Search">
  <div class="input-group-append">
    <button class="btn btn-success" type="submit">Go</button> 
  </div>
</div>
 
<div class="input-group mb-3">
  <input type="text" class="form-control" placeholder="Something clever..">
  <div class="input-group-append">
    <button class="btn btn-primary" type="button">OK</button> 
    <button class="btn btn-danger" type="button">Cancel</button> 
  </div>
</div>

设置下拉菜单

输入框中添加下拉菜单不需要使用 .dropdown 类。

Bootstrap4 输入框组

Bootstrap4 实例

<div class="input-group mt-3 mb-3">
  <div class="input-group-prepend">
    <button type="button" class="btn btn-outline-secondary dropdown-toggle" data-toggle="dropdown">
      选择网站
    </button>
    <div class="dropdown-menu">
      <a class="dropdown-item" href="https://www.google.com">GOOGLE</a>
      <a class="dropdown-item" href="https://www.runoob.com">RUNOOB</a>
      <a class="dropdown-item" href="https://www.taobao.com">TAOBAO</a>
    </div>
  </div>
  <input type="text" class="form-control" placeholder="网站地址">
</div>

输入框组标签

在输入框组通过在输入框组外围的 label 来设置标签，标签的 for 属性需要与输入框组的 id 对应，点击标签后可以聚焦输入框：

Bootstrap4 输入框组

Bootstrap4 实例

<label for="demo">Write your email here:</label>
<div class="input-group mb-3">
  <input type="text" class="form-control" placeholder="Email" id="demo" name="email">
  <div class="input-group-append">
    <span class="input-group-text">@runoob.com</span>
  </div>
</div>