Question

I’m trying to do something every time a new tab opens up, both via firefox starting and when a new tab is added after firefox starts. I’ve been following the example at:

https://developer.mozilla.org/en/Code_snippets/Tabbed_browser

So I have

var container = gBrowser.tabContainer;
container.addEventListener("TabOpen", tabAdded, false);
container.addEventListener("TabClose", tabClosed, false);

function tabAdded(event) {
alert("tabAdded!");
var browser = gBrowser.getBrowserForTab(event.target);
browser.pollingService = new PollingService(createGuid());
browser.pollingService.start();
}

And I have a similar function for the close. This works fine for when tabs are actually opened/closed, but I’ve run into a couple of problems.

Firstly, when Firefox opens, it has that initial tab already open, but the tabAdded event never fires for it. Similarly, when I shut down firefox, it never fires the TabClose for those tabs.

It seems like the correct thing to do in this case is to go through all of the tabs that are in the gBrowser.tabContainer and add my service to them as well, and do something similar for when Firefox closes. Unfortunately, I’m not quite sure how to hook in to know when Firefox closes (It’s also possible there’s a much better way to handle this, but I can’t think of one).

Secondly, gBrowser.tabContainer can be uninitialized sometimes when my initialization script runs; is there a particular event I should be listening to to know when I can safely add listeners to the tabContainer?

Answer 1

Use a load event listener to give the window time to be ready for you to add your Tab event listeners and create the polling service for the existing tab. Then use an unload event listener to do your cleanup.