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.
<h4><code>data-toggle="dropdown"</code> still required</h4>
<p>Regardless of whether you call your dropdown via JavaScript or instead use the data-api, <code>data-toggle="dropdown"</code> is always required to be present on the dropdown's trigger element.</p>
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### Options
*None.*
### Methods
#### $().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.
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<thstyle="width: 150px;">Event Type</th>
<th>Description</th>
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<td>show.bs.dropdown</td>
<td>This event fires immediately when the show instance method is called. The toggling anchor element is available as the <code>relatedTarget</code> property of the event.</td>
</tr>
<tr>
<td>shown.bs.dropdown</td>
<td>This event is fired when the dropdown has been made visible to the user (will wait for CSS transitions, to complete). The toggling anchor element is available as the <code>relatedTarget</code> property of the event.</td>
</tr>
<tr>
<td>hide.bs.dropdown</td>
<td>This event is fired immediately when the hide instance method has been called. The toggling anchor element is available as the <code>relatedTarget</code> property of the event.</td>
</tr>
<tr>
<td>hidden.bs.dropdown</td>
<td>This event is fired when the dropdown has finished being hidden from the user (will wait for CSS transitions, to complete). The toggling anchor element is available as the <code>relatedTarget</code> property of the event.</td>