YUI recommends YUI 3.
YUI 2 has been deprecated since 2011. This site acts as an archive for files and documentation.
The Button Control enables the creation of rich, graphical buttons that function like traditional HTML form buttons. Unlike tradition HTML form buttons, buttons created with the Button Control can have a label that is different from its value. With the inclusion of the optional Menu Control, the Button Control can also be used to create menu buttons and split buttons, controls that are not available natively in HTML. The Button Control can also be thought of as a way to create more visually engaging implementations of the browser's default radio-button and check-box controls.
The Button Control supports the following types: