What Is Event Bubbling?
What is event bubbling?
Answer out loud in under a minute: a definition, one concrete example, and one pitfall or trade-off.
Hints
Hint 1
Name the three phases, and one feature that depends on bubbling.
Solution
Show the approach
Answer
An event travels in three phases: capture down from window, the target, then bubble back up. Listeners run in the bubble phase unless registered with { capture: true }. Event delegation, one listener on a parent that handles events for its children, depends on bubbling. focus, blur, mouseenter and mouseleave do not bubble; focusin and focusout are their bubbling twins.