Basic Dropdown
A dropdown menu is a toggleable menu that allows the user to choose one value from a predefined list:
EXAMPLE:
<div class="dropdown">
<button class="btn btn-primary dropdown-toggle" type="button" data-toggle="dropdown">Dropdown Example
<span class="caret"></span></button>
<ul class="dropdown-menu">
<li><a href="#">HTML</a></li>
<li><a href="#">CSS</a></li>
<li><a href="#">JavaScript</a></li>
</ul>
</div>
Example Explained
The .dropdown class indicates a dropdown menu.
To open the dropdown menu, use a button or a link with a class of .dropdown-toggle and the data-toggle="dropdown" attribute.
The .caret class creates a caret arrow icon (), which indicates that the button is a dropdown.
Add the .dropdown-menu class to a <ul> element to actually build the dropdown menu.
Dropdown Divider
The .divider class is used to separate links inside the dropdown menu with a thin horizontal border:
EXAMPLE:
<li class="divider"></li>
Dropdown Header
The .dropdown-header class is used to add headers inside the dropdown menu:
EXAMPLE:
<li class="dropdown-header">Dropdown header 1</li>
Disable and Active items
Highlight a specific dropdown item with the .active class (adds a blue background color).
To disable an item in the dropdown menu, use the .disabled class (gets a light-grey text color and a "no-parking-sign" icon on hover):
EXAMPLE:
<li class="disabled"><a href="#">CSS</a></li>
<li class="active"><a href="#">HTML</a></li>
Dropdown Position
To right-align the dropdown, add the .dropdown-menu-right class to the element with .dropdown-menu:
EXAMPLE:
<ul class="dropdown-menu dropdown-menu-right">
Dropup
If you want the dropdown menu to expand upwards instead of downwards, change the <div> element with class="dropdown" to "dropup":
EXAMPLE:
<div class="dropup">
Dropdown Accessibility
To help improve accessibility for people using screen readers, you should include the following role and aria-* attributes, when creating a dropdown menu:
EXAMPLE:
<div class="dropdown">
<button class="btn btn-default dropdown-toggle" type="button" id="menu1" data-toggle="dropdown">Tutorials
<span class="caret"></span></button>
<ul class="dropdown-menu" role="menu" aria-labelledby="menu1">
<li role="presentation"><a role="menuitem" href="#">HTML</a></li>
<li role="presentation"><a role="menuitem" href="#">CSS</a></li>
<li role="presentation"><a role="menuitem" href="#">JavaScript</a></li>
<li role="presentation" class="divider"></li>
<li role="presentation"><a role="menuitem" href="#">About Us</a></li>
</ul>
</div>