Proyectos de Subversion Moodle

---

layout: docs

title: Buttons

description: Use Bootstrap's custom button styles for actions in forms, dialogs, and more with support for multiple sizes, states, and more.

group: components

toc: true

---

## Examples

Bootstrap includes several predefined button styles, each serving its own semantic purpose, with a few extras thrown in for more control.

{{< example >}}

{{< buttons.inline >}}

{{- range (index $.Site.Data "theme-colors") }}

<button type="button" class="btn btn-{{ .name }}">{{ .name | title }}</button>

{{- end -}}

{{< /buttons.inline >}}

<button type="button" class="btn btn-link">Link</button>

{{< /example >}}

{{< callout warning >}}

{{< partial "callout-warning-color-assistive-technologies.md" >}}

{{< /callout >}}

## Disable text wrapping

If you don't want the button text to wrap, you can add the `.text-nowrap` class to the button. In Sass, you can set `$btn-white-space: nowrap` to disable text wrapping for each button.

## Button tags

The `.btn` classes are designed to be used with the `<button>` element. However, you can also use these classes on `<a>` or `<input>` elements (though some browsers may apply a slightly different rendering).

When using button classes on `<a>` elements that are used to trigger in-page functionality (like collapsing content), rather than linking to new pages or sections within the current page, these links should be given a `role="button"` to appropriately convey their purpose to assistive technologies such as screen readers.

{{< example >}}

<a class="btn btn-primary" href="#" role="button">Link</a>

<button class="btn btn-primary" type="submit">Button</button>

<input class="btn btn-primary" type="button" value="Input">

<input class="btn btn-primary" type="submit" value="Submit">

<input class="btn btn-primary" type="reset" value="Reset">

{{< /example >}}

## Outline buttons

In need of a button, but not the hefty background colors they bring? Replace the default modifier classes with the `.btn-outline-*` ones to remove all background images and colors on any button.

{{< example >}}

{{< buttons.inline >}}

{{- range (index $.Site.Data "theme-colors") }}

<button type="button" class="btn btn-outline-{{ .name }}">{{ .name | title }}</button>

{{- end -}}

{{< /buttons.inline >}}

{{< /example >}}

{{< callout info >}}

Some of the button styles use a relatively light foreground color, and should only be used on a dark background in order to have sufficient contrast.

{{< /callout >}}

## Sizes

Fancy larger or smaller buttons? Add `.btn-lg` or `.btn-sm` for additional sizes.

{{< example >}}

<button type="button" class="btn btn-primary btn-lg">Large button</button>

<button type="button" class="btn btn-secondary btn-lg">Large button</button>

{{< /example >}}

{{< example >}}

<button type="button" class="btn btn-primary btn-sm">Small button</button>

<button type="button" class="btn btn-secondary btn-sm">Small button</button>

{{< /example >}}

Create block level buttons—those that span the full width of a parent—by adding `.btn-block`.

{{< example >}}

<button type="button" class="btn btn-primary btn-lg btn-block">Block level button</button>

<button type="button" class="btn btn-secondary btn-lg btn-block">Block level button</button>

{{< /example >}}

## Active state

Buttons will appear pressed when active with a darker background, darker border, and, when shadows are enabled, an inset shadow. **There's no need to add a class to `<button>`s as they use a pseudo-class**. However, you can still force the same active appearance with `.active` (and include the <code>aria-pressed="true"</code> attribute) should you need to replicate the state programmatically.

{{< example >}}

<a href="#" class="btn btn-primary btn-lg active" role="button" aria-pressed="true">Primary link</a>

<a href="#" class="btn btn-secondary btn-lg active" role="button" aria-pressed="true">Link</a>

{{< /example >}}

## Disabled state

Make buttons look inactive by adding the `disabled` boolean attribute to any `<button>` element.

{{< example >}}

<button type="button" class="btn btn-lg btn-primary" disabled>Primary button</button>

<button type="button" class="btn btn-secondary btn-lg" disabled>Button</button>

{{< /example >}}

Disabled buttons using the `<a>` element behave a bit different:

- `<a>`s don't support the `disabled` attribute, so you must add the `.disabled` class to make it visually appear disabled.

- Some future-friendly styles are included to disable all `pointer-events` on anchor buttons. In browsers which support that property, you won't see the disabled cursor at all.

- Disabled buttons using `<a>` should include the `aria-disabled="true"` attribute to indicate the state of the element to assistive technologies.

- Disabled buttons using `<a>` *should not* include the `href` attribute.

{{< example >}}

<a class="btn btn-primary btn-lg disabled" role="button" aria-disabled="true">Primary link</a>

<a class="btn btn-secondary btn-lg disabled" role="button" aria-disabled="true">Link</a>

{{< /example >}}

### Link functionality caveat

To cover cases where you have to keep the `href` attribute on a disabled link, the `.disabled` class uses `pointer-events: none` to try to disable the link functionality of `<a>`s. Note that this CSS property is not yet standardized for HTML, but all modern browsers support it. In addition, even in browsers that do support `pointer-events: none`, keyboard navigation remains unaffected, meaning that sighted keyboard users and users of assistive technologies will still be able to activate these links. So to be safe, in addition to `aria-disabled="true"`, also include a `tabindex="-1"` attribute on these links to prevent them from receiving keyboard focus, and use custom JavaScript to disable their functionality altogether.

{{< example >}}

<a href="#" class="btn btn-primary btn-lg disabled" tabindex="-1" role="button" aria-disabled="true">Primary link</a>

<a href="#" class="btn btn-secondary btn-lg disabled" tabindex="-1" role="button" aria-disabled="true">Link</a>

{{< /example >}}

## Button plugin

Do more with buttons. Control button states or create groups of buttons for more components like toolbars.

### Toggle states

Add `data-toggle="button"` to toggle a button's `active` state. If you're pre-toggling a button, you must manually add the `.active` class **and** `aria-pressed="true"` to the `<button>`.

{{< example >}}

<button type="button" class="btn btn-primary" data-toggle="button" aria-pressed="false">

  Single toggle

</button>

{{< /example >}}

### Checkbox and radio buttons

Bootstrap's `.button` styles can be applied to other elements, such as `<label>`s, to provide checkbox or radio style button toggling. Add `data-toggle="buttons"` to a `.btn-group` containing those modified buttons to enable their toggling behavior via JavaScript and add `.btn-group-toggle` to style the `<input>`s within your buttons. **Note that you can create single input-powered buttons or groups of them.**

The checked state for these buttons is **only updated via `click` event** on the button. If you use another method to update the input—e.g., with `<input type="reset">` or by manually applying the input's `checked` property—you'll need to toggle `.active` on the `<label>` manually.

Note that pre-checked buttons require you to manually add the `.active` class to the input's `<label>`.

{{< example >}}

<div class="btn-group-toggle" data-toggle="buttons">

  <label class="btn btn-secondary active">

    <input type="checkbox" checked> Checked

  </label>

</div>

{{< /example >}}

{{< example >}}

<div class="btn-group btn-group-toggle" data-toggle="buttons">

  <label class="btn btn-secondary active">

    <input type="radio" name="options" id="option1" checked> Active

  </label>

  <label class="btn btn-secondary">

    <input type="radio" name="options" id="option2"> Radio

  </label>

  <label class="btn btn-secondary">

    <input type="radio" name="options" id="option3"> Radio

  </label>

</div>

{{< /example >}}

### Methods

| Method | Description |

| --- | --- |

| `$().button('toggle')` | Toggles push state. Gives the button the appearance that it has been activated. |

| `$().button('dispose')` | Destroys an element's button. |