By using our site, you acknowledge that you have read and understand our Cookie Policy, Privacy Policy, and our Terms of Service. Notice that the event propagation does not originate from the button itself. The actual event is called DOMContentLoaded. Lightning Inter-Component Communication Patterns, Then, the action callback resumes or stops the event propagation based on the server response.

For the DOMContentLoaded event, however (to quote MDN): The DOMContentLoaded event fires when the initial HTML document has been completely loaded and parsed, without waiting for stylesheets, images, and subframes to finish loading. I assume that just having a simple