Bootstrap输入组

Bootstrap输入组允许用户在文本输入、自定义选择和自定义文件输入的任一侧添加文本、按钮或按钮组，可以轻松扩展窗体控件。例如在输入的任一侧放置一个附加组件或按钮。也可以在输入的两侧各放置一个。记住将label放在输入组之外。

一、基本示例

在输入的任一侧放置一个附加组件或按钮。也可以在输入的两侧各放置一个。记住将label放在输入组之外。

<div class="input-group mb-3">
<div class="input-group-prepend">
<span class="input-group-text" id="basic-addon1">@</span>
</div>
<input type="text" class="form-control" placeholder="Username" aria-label="Username" aria-describedby="basic-addon1">
</div>
<div class="input-group mb-3">
<input type="text" class="form-control" placeholder="Recipient's username" aria-label="Recipient's username" aria-describedby="basic-addon2">
<div class="input-group-append">
<span class="input-group-text" id="basic-addon2">@example.com</span>
</div>
</div>
<label for="basic-url">Your vanity URL</label>
<div class="input-group mb-3">
<div class="input-group-prepend">
<span class="input-group-text" id="basic-addon3">https://example.com/users/</span>
</div>
<input type="text" class="form-control" id="basic-url" aria-describedby="basic-addon3">
</div>
<div class="input-group mb-3">
<div class="input-group-prepend">
<span class="input-group-text">$</span>
</div>
<input type="text" class="form-control" aria-label="Amount (to the nearest dollar)">
<div class="input-group-append">
<span class="input-group-text">.00</span>
</div>
</div>
<div class="input-group">
<div class="input-group-prepend">
<span class="input-group-text">With textarea</span>
</div>
<textarea class="form-control" aria-label="With textarea"></textarea>
</div>

二、包装

默认情况下，输入组通过flex-wrap: wrap进行包装，以便在输入组中容纳自定义表单字段验证。可以使用nowrap禁用此功能。

<div class="input-group flex-nowrap">
<div class="input-group-prepend">
<span class="input-group-text" id="addon-wrapping">@</span>
</div>
<input type="text" class="form-control" placeholder="Username" aria-label="Username" aria-describedby="addon-wrapping">
</div>

三、大小

将相对窗体大小调整类添加到.input-group 。输入组本身和其中的内容将自动调整大小，无需在每个元素上重复窗体控件大小调整类。

注意：不支持对单个输入组元素进行大小调整。

<div class="input-group input-group-sm mb-3">
<div class="input-group-prepend">
<span class="input-group-text" id="inputGroup-sizing-sm">Small</span>
</div>
<input type="text" class="form-control" aria-label="Sizing example input" aria-describedby="inputGroup-sizing-sm">
</div>
<div class="input-group mb-3">
<div class="input-group-prepend">
<span class="input-group-text" id="inputGroup-sizing-default">Default</span>
</div>
<input type="text" class="form-control" aria-label="Sizing example input" aria-describedby="inputGroup-sizing-default">
</div>
<div class="input-group input-group-lg">
<div class="input-group-prepend">
<span class="input-group-text" id="inputGroup-sizing-lg">Large</span>
</div>
<input type="text" class="form-control" aria-label="Sizing example input" aria-describedby="inputGroup-sizing-lg">
</div>

四、复选框和单选按钮

将任何复选框或单选选项放在输入组的插件中，而不是文本中。

<div class="input-group mb-3">
<div class="input-group-prepend">
<div class="input-group-text">
<input type="checkbox" aria-label="Checkbox for following text input">
</div>
</div>
<input type="text" class="form-control" aria-label="Text input with checkbox">
</div>
<div class="input-group">
<div class="input-group-prepend">
<div class="input-group-text">
<input type="radio" aria-label="Radio button for following text input">
</div>
</div>
<input type="text" class="form-control" aria-label="Text input with radio button">
</div>

五、多输入框

虽然外观上支持多个input，但验证样式仅适用于具有单个input的输入组。

<div class="input-group">
<div class="input-group-prepend">
<span class="input-group-text">First and last name</span>
</div>
<input type="text" aria-label="First name" class="form-control">
<input type="text" aria-label="Last name" class="form-control">
</div>

六、多个附加组件

支持多个附加组件，可以与复选框和单选输入版本混合使用。

<div class="input-group mb-3">
<div class="input-group-prepend">
<span class="input-group-text">$</span>
<span class="input-group-text">0.00</span>
</div>
<input type="text" class="form-control" aria-label="Dollar amount (with dot and two decimal places)">
</div>
<div class="input-group">
<input type="text" class="form-control" aria-label="Dollar amount (with dot and two decimal places)">
<div class="input-group-append">
<span class="input-group-text">$</span>
<span class="input-group-text">0.00</span>
</div>
</div>

七、附加按钮

<div class="input-group mb-3">
<div class="input-group-prepend">
<button class="btn btn-outline-secondary" type="button" id="button-addon1">Button</button>
</div>
<input type="text" class="form-control" placeholder="" aria-label="Example text with button addon" aria-describedby="button-addon1">
</div>
<div class="input-group mb-3">
<input type="text" class="form-control" placeholder="Recipient's username" aria-label="Recipient's username" aria-describedby="button-addon2">
<div class="input-group-append">
<button class="btn btn-outline-secondary" type="button" id="button-addon2">Button</button>
</div>
</div>
<div class="input-group mb-3">
<div class="input-group-prepend" id="button-addon3">
<button class="btn btn-outline-secondary" type="button">Button</button>
<button class="btn btn-outline-secondary" type="button">Button</button>
</div>
<input type="text" class="form-control" placeholder="" aria-label="Example text with two button addons" aria-describedby="button-addon3">
</div>
<div class="input-group">
<input type="text" class="form-control" placeholder="Recipient's username" aria-label="Recipient's username with two button addons" aria-describedby="button-addon4">
<div class="input-group-append" id="button-addon4">
<button class="btn btn-outline-secondary" type="button">Button</button>
<button class="btn btn-outline-secondary" type="button">Button</button>
</div>
</div>

八、带下拉列表的按钮

<div class="input-group mb-3">
<div class="input-group-prepend">
<button class="btn btn-outline-secondary dropdown-toggle" type="button" data-toggle="dropdown" aria-expanded="false">Dropdown</button>
<div class="dropdown-menu">
<a class="dropdown-item" href="#">Action</a>
<a class="dropdown-item" href="#">Another action</a>
<a class="dropdown-item" href="#">Something else here</a>
<div role="separator" class="dropdown-divider"></div>
<a class="dropdown-item" href="#">Separated link</a>
</div>
</div>
<input type="text" class="form-control" aria-label="Text input with dropdown button">
</div>
<div class="input-group">
<input type="text" class="form-control" aria-label="Text input with dropdown button">
<div class="input-group-append">
<button class="btn btn-outline-secondary dropdown-toggle" type="button" data-toggle="dropdown" aria-expanded="false">Dropdown</button>
<div class="dropdown-menu">
<a class="dropdown-item" href="#">Action</a>
<a class="dropdown-item" href="#">Another action</a>
<a class="dropdown-item" href="#">Something else here</a>
<div role="separator" class="dropdown-divider"></div>
<a class="dropdown-item" href="#">Separated link</a>
</div>
</div>
</div>

九、分割按钮

<div class="input-group mb-3">
<div class="input-group-prepend">
<button type="button" class="btn btn-outline-secondary">Action</button>
<button type="button" class="btn btn-outline-secondary dropdown-toggle dropdown-toggle-split" data-toggle="dropdown" aria-expanded="false">
<span class="sr-only">Toggle Dropdown</span>
</button>
<div class="dropdown-menu">
<a class="dropdown-item" href="#">Action</a>
<a class="dropdown-item" href="#">Another action</a>
<a class="dropdown-item" href="#">Something else here</a>
<div role="separator" class="dropdown-divider"></div>
<a class="dropdown-item" href="#">Separated link</a>
</div>
</div>
<input type="text" class="form-control" aria-label="Text input with segmented dropdown button">
</div>
<div class="input-group">
<input type="text" class="form-control" aria-label="Text input with segmented dropdown button">
<div class="input-group-append">
<button type="button" class="btn btn-outline-secondary">Action</button>
<button type="button" class="btn btn-outline-secondary dropdown-toggle dropdown-toggle-split" data-toggle="dropdown" aria-expanded="false">
<span class="sr-only">Toggle Dropdown</span>
</button>
<div class="dropdown-menu">
<a class="dropdown-item" href="#">Action</a>
<a class="dropdown-item" href="#">Another action</a>
<a class="dropdown-item" href="#">Something else here</a>
<div role="separator" class="dropdown-divider"></div>
<a class="dropdown-item" href="#">Separated link</a>
</div>
</div>
</div>

十、自定义表单

输入组包括对自定义选择和自定义文件输入的支持。不支持浏览器的默认版本。

1、自定义选择

<div class="input-group mb-3">
<div class="input-group-prepend">
<label class="input-group-text" for="inputGroupSelect01">Options</label>
</div>
<select class="custom-select" id="inputGroupSelect01">
<option selected>Choose...</option>
<option value="1">One</option>
<option value="2">Two</option>
<option value="3">Three</option>
</select>
</div>
<div class="input-group mb-3">
<select class="custom-select" id="inputGroupSelect02">
<option selected>Choose...</option>
<option value="1">One</option>
<option value="2">Two</option>
<option value="3">Three</option>
</select>
<div class="input-group-append">
<label class="input-group-text" for="inputGroupSelect02">Options</label>
</div>
</div>
<div class="input-group mb-3">
<div class="input-group-prepend">
<button class="btn btn-outline-secondary" type="button">Button</button>
</div>
<select class="custom-select" id="inputGroupSelect03" aria-label="Example select with button addon">
<option selected>Choose...</option>
<option value="1">One</option>
<option value="2">Two</option>
<option value="3">Three</option>
</select>
</div>
<div class="input-group">
<select class="custom-select" id="inputGroupSelect04" aria-label="Example select with button addon">
<option selected>Choose...</option>
<option value="1">One</option>
<option value="2">Two</option>
<option value="3">Three</option>
</select>
<div class="input-group-append">
<button class="btn btn-outline-secondary" type="button">Button</button>
</div>
</div>

2、自定义文件输入

下面示例使用自定义文件浏览器组件，该组件依赖于单独的 bs-custom-file-input 插件。

<div class="input-group mb-3">
<div class="input-group-prepend">
<span class="input-group-text" id="inputGroupFileAddon01">Upload</span>
</div>
<div class="custom-file">
<input type="file" class="custom-file-input" id="inputGroupFile01" aria-describedby="inputGroupFileAddon01">
<label class="custom-file-label" for="inputGroupFile01">Choose file</label>
</div>
</div>
<div class="input-group mb-3">
<div class="custom-file">
<input type="file" class="custom-file-input" id="inputGroupFile02">
<label class="custom-file-label" for="inputGroupFile02" aria-describedby="inputGroupFileAddon02">Choose file</label>
</div>
<div class="input-group-append">
<span class="input-group-text" id="inputGroupFileAddon02">Upload</span>
</div>
</div>
<div class="input-group mb-3">
<div class="input-group-prepend">
<button class="btn btn-outline-secondary" type="button" id="inputGroupFileAddon03">Button</button>
</div>
<div class="custom-file">
<input type="file" class="custom-file-input" id="inputGroupFile03" aria-describedby="inputGroupFileAddon03">
<label class="custom-file-label" for="inputGroupFile03">Choose file</label>
</div>
</div>
<div class="input-group">
<div class="custom-file">
<input type="file" class="custom-file-input" id="inputGroupFile04" aria-describedby="inputGroupFileAddon04">
<label class="custom-file-label" for="inputGroupFile04">Choose file</label>
</div>
<div class="input-group-append">
<button class="btn btn-outline-secondary" type="button" id="inputGroupFileAddon04">Button</button>
</div>
</div>

十一、可及性

确保所有表单控件都具有适当的辅助名称，以便将其用途传达给辅助技术的用户。实现此目的的最简单方法是使用元素，或者（对于按钮）将足够描述性的文本作为内容的一部分。例如：

<label><button>...</button></label>

对于无法包含可见或适当的文本内容的情况，还有其他方法仍可提供辅助名称，例如：

1、使用类隐藏的元素并添加 .sr-only类。

2、指向可用作标签的现有元素，使用 aria-labelledby属性。

3、提供属性 title。

4、使用 aria-label 属性。

如果这些都不存在，辅助技术可能会求助于使用该属性作为 on 和元素的辅助名称的回退。本节中的示例提供了一些建议的特定于案例的方法。

虽然使用视觉上隐藏的内容（如 <div>、<span> 甚至内容，一旦表单字段包含内容就会消失）将使辅助技术用户受益，但对于某些用户来说，缺少可见的标签文本可能仍然是个问题。某种形式的可见标签通常是可访问性和可用性的最佳方法。