role and provide a labelIn order for assistive technologies – such as screen readers – to convey that a series of buttons is grouped, an appropriate role attribute needs to be provided. For button groups, this would be role="group", while toolbars should have a role="toolbar".
One exception are groups which only contain a single control (for instance the justified button groups with <button> elements) or a dropdown.
In addition, groups and toolbars should be given an explicit label, as most assistive technologies will otherwise not announce them, despite the presence of the correct role attribute. In the examples provided here, we use aria-label, but alternatives such as aria-labelledby can also be used.
Due to the specific HTML and CSS used to justify buttons (namely display: table-cell), the borders between them are doubled. In regular button groups, margin-left: -1px is used to stack the borders instead of removing them. However, margin doesn't work with display: table-cell. As a result, depending on your customizations to Bootstrap, you may wish to remove or re-color the borders.
If the <a> elements are used to act as buttons – triggering in-page functionality, rather than navigating to another document or section within the current page – they should also be given an appropriate role="button".