Salesforce JavaScript Developer Practice Exam 2025 – 400 Free Practice Questions to Pass the Exam

The concept of event bubbling in JavaScript refers to the way events propagate through the Document Object Model (DOM). When an event occurs on a target element, the event first runs on that element and then "bubbles up" to its parent elements in the hierarchy. This means that the event will be received by the target element, and then it continues to propagate upwards, allowing each ancestor of the target to potentially handle the event as well.

This propagation allows for event delegation, which is a useful technique where a single event listener can manage events for multiple child elements by attaching the listener to a common ancestor. This can enhance performance and organization in managing events, especially when dealing with a large number of similar elements.

In contrast to this, other options describe alternative behaviors that do not align with the concept of event bubbling. For example, events propagating down from parent to child refers to a different mechanism known as event capturing, while stating that events do not propagate through the DOM ignores the core feature of event propagation. Lastly, the idea that events are handled only at the target element negates the functionality that bubbling offers, which allows for multiple levels of event handling. Hence, the correct understanding of event bubbling is encapsulated in the notion that events start from