What is meant by event bubbling?

When an event resides in an element inside another element and both elements have registered a handle to that event, the HTML DOM API uses event bubbling as a form of event propagation. It is a procedure that begins with the element that caused the event and then cascades up to the elements in the hierarchy that contain it.

• A sort of event propagation known as "event bubbling" occurs when an event first occurs on the innermost target element and then sequentially occurs on the ancestors (parents) of the target element in the same nesting hierarchy until it occurs on the outermost DOM element or document object (Provided the handler is initialized).