Start here. This is the direct spoken answer to practice first.
Why this question matters
Event propagation sits underneath everyday interactions such as menus, tables, dialogs, and forms. Understanding it helps prevent duplicate handlers, accidental clicks, broken nested controls, and fragile code around dynamically rendered elements.
A DOM event travels through a capture phase from the document toward the target, runs at the target, and usually bubbles back through its ancestors. event.target is where the event started, while event.currentTarget is the element whose listener is currently running. preventDefault() cancels a browser action such as following a link or submitting a form when the event allows it; stopPropagation() stops the event from continuing through the propagation path. Event delegation uses one listener on a stable ancestor and inspects the target to handle events from many current or future descendants.