User: iframe.onerror won't run when there's an error for one webapp that I have but not for the other. THey have different parents of course. what are some possible reasons this could happen. Be very concise.
ChatGPT:
- Different browser behavior.
- Same-origin policy restrictions.
- Error in error-handling code.
- Incorrect event listener attachment.
- Parent window interfering with events.
- iframe sandbox attribute limiting functionality.