Salesforce JavaScript Developer Practice Exam

In the context of event listeners, what is the order of execution when an inner div is clicked?

1. displayOuterMessage, displayInnerMessage

2. displayInnerMessage, displayOuterMessage

3. displayInnerMessage only

4. displayOuterMessage only

The correct answer is: displayOuterMessage, displayInnerMessage

In the context of event listeners within the DOM (Document Object Model) in JavaScript, event propagation occurs in two main phases: the capturing phase and the bubbling phase. Given the scenario of clicking an inner div, event listeners attached to both the inner and outer divs will be executed based on this propagation mechanism. When the inner div is clicked, the event first targets the div itself and then propagates upwards to its parent elements. This is known as the bubbling phase, where the event travels from the target element (the inner div) back up to the root of the document. As such, if there are event listeners attached to both the inner div and the outer div, the inner div's event listener will execute first, followed by the outer div's listener. Therefore, in the scenario presented, the execution order will indeed start with the event listener associated with the inner div (which is likely handling the click event) and then move up to execute the event listener associated with the outer div. This results in the correct ordering of execution being that the function for the outer div runs after that for the inner div. This understanding of event propagation is fundamental in JavaScript, particularly when dealing with nested element interactions, and it explains why the