Simple test page for drop down and combobuttons. Note that not all behavior is fully implemented - for example removing focus from a button should close any open menus but it does not.
Here to easily enable forms mode on in JAWS
Here is an example menu button. Press Enter or space to open a menu. With menu open, press down arrow to set focus into menu. Press up/down arrows to cycle through menu items. Press enter to invoke menu item. Press escape to close menu and return focus to button.
Here is a combo button. It is actually given a role or menu. Press enter to execute the default action of save. Press the down arrow to traverse through the other choices. Since the role is menu, use of the space key to invoke the action is not implemented. Clicking on the button will perform the default action, clicking on the arrow will open the list of other choices. Note: mouse and keyboard interaction not implemented - use only keyboard or only mouse.
Here is a combo button with two tab stops - one for button and another for arrow. The first tab stop is given a role of button. Pressing enter or space on the first tab stop with value, Save, performs the default action. The second tab stop, the down arrow image with a text alternative of options, is given a role of button with a popup. Pressing down arrow or space on the arrow image opens the menu.