Module default_actions 

Default Action Processing for Keyboard Events

This module implements W3C-compliant default actions for keyboard events. Default actions are built-in behaviors that occur after event dispatch, unless event.prevent_default() was called.

W3C Event Model

Per DOM Level 2/3 and W3C UI Events:

1. Event is dispatched through capture → target → bubble phases
2. Callbacks can call event.prevent_default() to cancel default action
3. After dispatch, if not prevented, the default action is performed

Keyboard Default Actions

Key	Modifiers	Default Action
Tab	None	Focus next element
Tab	Shift	Focus previous element
Enter	None	Activate focused element (if activatable)
Space	None	Activate focused element (if activatable)
Escape	None	Clear focus

Activation Behavior (HTML5)

Per HTML5 spec, elements with “activation behavior” can be activated via Enter or Space. This generates a synthetic click event:

• Button elements
• Anchor elements with href
• Input elements (submit, button, checkbox, radio)
• Any element with a click callback

See: https://html.spec.whatwg.org/multipage/interaction.html#activation-behavior

Functions

create_activation_click_event

Create a synthetic click event for element activation.

default_action_to_focus_target

Convert a DefaultAction to a FocusTarget for the focus manager.

determine_keyboard_default_action

Determine the default action for a keyboard event.