mdb-ui-kit/docs/components/dropdowns.md
2016-03-17 17:25:31 -05:00

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---
layout: docs
title: Dropdowns
group: components
---
[//]: # DO NOT EDIT IT WILL BE OVERWRITTEN - copy of bootstrap documentation generated by gulp docs:copy:bs-docs
{% callout info %}
**Bootstrap Reference Documentation**
This is a part of the reference documentation from <a href="http://getbootstrap.com">Bootstrap</a>.
It is included here to demonstrate rendering with Material Design for Bootstrap default styling.
See the <a href="/material-design/buttons">Material Design</a> section for more elements and customization options.
{% endcallout %}
Dropdowns are toggleable, contextual overlays for displaying lists of links and more. They're made interactive with the included Bootstrap dropdown JavaScript plugin. They're toggled by clicking, not by hovering; this is [an intentional design decision.](http://markdotto.com/2012/02/27/bootstrap-explained-dropdowns/)
## Contents
* Will be replaced with the ToC, excluding the "Contents" header
{:toc}
## Example
Wrap the dropdown's trigger and the dropdown menu within `.dropdown`, or another element that declares `position: relative;`. Then, add the menu's HTML.
{% example html %}
<div class="dropdown open">
<button class="btn btn-secondary dropdown-toggle" type="button" id="dropdownMenu1" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
Dropdown
</button>
<div class="dropdown-menu" aria-labelledby="dropdownMenu1">
<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>
</div>
{% endexample %}
### Button elements
You can optionally use `<button>` elements in your dropdowns instead of `<a>`s.
{% example html %}
<div class="dropdown open">
<button class="btn btn-secondary dropdown-toggle" type="button" id="dropdownMenu2" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
Dropdown
</button>
<div class="dropdown-menu" aria-labelledby="dropdownMenu2">
<button class="dropdown-item" type="button">Action</button>
<button class="dropdown-item" type="button">Another action</button>
<button class="dropdown-item" type="button">Something else here</button>
</div>
</div>
{% endexample %}
## Alignment
By default, a dropdown menu is automatically positioned 100% from the top and along the left side of its parent. Add `.dropdown-menu-right` to a `.dropdown-menu` to right align the dropdown menu.
{% callout info %}
**Heads up!** Dropdowns are positioned only with CSS and may need some additional styles for exact alignment.
{% endcallout %}
{% example html %}
<div class="btn-group">
<button type="button" class="btn btn-secondary dropdown-toggle" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
This dropdown's menu is right-aligned
</button>
<div class="dropdown-menu dropdown-menu-right">
<button class="dropdown-item" type="button">Action</button>
<button class="dropdown-item" type="button">Another action</button>
<button class="dropdown-item" type="button">Something else here</button>
</div>
</div>
{% endexample %}
## Menu headers
Add a header to label sections of actions in any dropdown menu.
{% example html %}
<div class="dropdown-menu">
<h6 class="dropdown-header">Dropdown header</h6>
<a class="dropdown-item" href="#">Action</a>
<a class="dropdown-item" href="#">Another action</a>
</div>
{% endexample %}
## Menu dividers
Separate groups of related menu items with a divider.
{% example html %}
<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 class="dropdown-divider"></div>
<a class="dropdown-item" href="#">Separated link</a>
</div>
{% endexample %}
## Disabled menu items
Add `.disabled` to items in the dropdown to **style them as disabled**.
{% example html %}
<div class="dropdown-menu">
<a class="dropdown-item" href="#">Regular link</a>
<a class="dropdown-item disabled" href="#">Disabled link</a>
<a class="dropdown-item" href="#">Another link</a>
</div>
{% endexample %}
## Usage
Via data attributes or JavaScript, the dropdown plugin toggles hidden content (dropdown menus) by toggling the `.open` class on the parent list item.
On mobile devices, opening a dropdown adds a `.dropdown-backdrop` as a tap area for closing dropdown menus when tapping outside the menu, a requirement for proper iOS support. **This means that switching from an open dropdown menu to a different dropdown menu requires an extra tap on mobile.**
Note: The `data-toggle="dropdown"` attribute is relied on for closing dropdown menus at an application level, so it's a good idea to always use it.
### Via data attributes
Add `data-toggle="dropdown"` to a link or button to toggle a dropdown.
{% highlight html %}
<div class="dropdown">
<button id="dLabel" type="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
Dropdown trigger
</button>
<div class="dropdown-menu" aria-labelledby="dLabel">
...
</div>
</div>
{% endhighlight %}
To keep URLs intact with link buttons, use the `data-target` attribute instead of `href="#"`.
{% highlight html %}
<div class="dropdown">
<a id="dLabel" data-target="#" href="http://example.com" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
Dropdown trigger
</a>
<div class="dropdown-menu" aria-labelledby="dLabel">
...
</div>
</div>
{% endhighlight %}
### Via JavaScript
Call the dropdowns via JavaScript:
{% highlight js %}
$('.dropdown-toggle').dropdown()
{% endhighlight %}
{% callout info %}
#### `data-toggle="dropdown"` still required
Regardless of whether you call your dropdown via JavaScript or instead use the data-api, `data-toggle="dropdown"` is always required to be present on the dropdown's trigger element.
{% endcallout %}
### Options
*None.*
### Methods
| Method | Description |
| --- | --- |
| `$().dropdown('toggle')` | Toggles the dropdown menu of a given navbar or tabbed navigation. |
### Events
All dropdown events are fired at the `.dropdown-menu`'s parent element and have a `relatedTarget` property, whose value is the toggling anchor element.
| Event | Description |
| --- | --- |
| `show.bs.dropdown` | This event fires immediately when the show instance method is called. |
| `shown.bs.dropdown` | This event is fired when the dropdown has been made visible to the user (will wait for CSS transitions, to complete). |
| `hide.bs.dropdown` | This event is fired immediately when the hide instance method has been called. |
| `hidden.bs.dropdown`| This event is fired when the dropdown has finished being hidden from the user (will wait for CSS transitions, to complete). |
{% highlight js %}
$('#myDropdown').on('show.bs.dropdown', function () {
// do something…
})
{% endhighlight %}