Use the button classes on an <a>, <button>, or <input> element.
While button classes can be used on <a> and <button> elements, only <button> elements are supported within our nav and navbar components.
Links acting as buttons
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".
As a best practice, we highly recommend using the <button> element whenever possible to ensure matching cross-browser rendering.
Among other things, there's a bug in Firefox <30 that prevents us from setting the line-height of <input>-based buttons, causing them to not exactly match the height of other buttons on Firefox.