How to capture the Ajax event that periodically refreshes the gmail inbox

Question

I'm trying to write a Greasemonkey script that works with Gmail. I know how to create javascript that reacts to the user clicking on the Inbox link or the the Refresh link. My problem is that Gmail periodically refreshes the inbox with new conversations and I have no way of capturing this event. Is there any way to capture periodical Ajax events in javascript?

Answer 1

You could try replacing the window.setTimeout function (and possibly window.setInterval) with your own functions:

window._setTimeout = window.setTimeout;
window.setTimeout = function(func, delay) {
    return window._setTimeout(function() {
        // Your code goes here, before the client function is called
        alert('A timeout event just fired!');

        if (typeof func == 'string') {
            eval(func);
        } else {
            func();
        }
    }, delay);
}

Answer 2

I tried Miles' excellent suggestion above, but unfortunately it doesn't work because Gmail has already called the original setTimeout function before I have a chance to change it in my Greasemonkey script.

The only thing I can do is somehow react to the changes that Gmail makes when it periodically refreshes the inbox. I found that there are several DOM related events that fire when a node is added or removed:

http://www.w3.org/TR/DOM-Level-3-Events/events.html#event-DOMNodeInserted

Since Gmail is updating the DOM with my latest emails, I can listen for these DOM events (I'm using DOMNodeInserted) and react to the changes.

It isn't elegant, but it works.