Firefox Adds Listener for Browser Error

Question

I use the online add-on builder to create a small add-on. We can get the page and url loading using this: https://addons.mozilla.org/en-US/developers/docs/sdk/latest/dev-guide/tutorials/listen-for-page-load.html

I tested above and it works.

But how to add a listener for browser error messages, such as Problem loading page (if the Internet connection fails). I want to catch this error (for example, the warning "error loading page"). how is this possible?

Answer 1

• Page Load Interception lists a few things that allow you to view HTTP traffic.
• "Recognizing page load failure" contains a very brief description of how you can do this with WebProgressListeners. (It is linked to the page above, but the link is outdated and broken.)

It doesn't seem to be any Jetpack-specific function for this kind of thing, so you might be stuck in one of these much more detailed and low-level solutions. But I don’t know what I'm talking about, so maybe post to mozilla.dev.extensions before taking the floor on this. :) Good luck!

Answer 2

This js can be entered -

 window.onerror = function(message, url, linenumber) { alert("Err"+message); }