Event bubbling is a concept in the Document Object Model (DOM) of JavaScript that occurs when an element receives an event, and that event bubbles up to its parent and ancestor elements in the DOM tree until it gets to the root element. It is a method of event propagation in the HTML DOM API when an event occurs in an element inside another element, and both elements have registered a handle for that event.

When an event occurs on an element, it first runs the handlers on that element, then on its parent element, and so on upwards till the document object. This process is called "bubbling" because events "bubble" from the inner element up through parents like a bubble in the water.

The "Event Bubbling" behavior makes it possible for you to handle an event in a parent element instead of the actual element that received the event. This is useful when you have multiple elements that need to respond to the same event, such as a click event. By handling the event on a parent element, you can avoid having to add event listeners to each individual child element.

To handle events that bubble, you can use the addEventListener() method, which takes three arguments: the type of event, the function to call when the event occurs, and a boolean value that indicates whether the event should be handled during the capturing phase or the bubbling phase. By default, events are handled during the bubbling phase.

In summary, event bubbling is a way for events to propagate up the DOM tree from the innermost element to the outermost element. It allows you to handle events on parent elements instead of individual child elements, making your code more efficient and easier to maintain.