Detect tabbox tab change in XUL

Question

What's the best way to detect switching between tabs inside a tabbox? In particular, I need to detect when a certain tab is opened, and when the user leaves it (switches to another tab).

I'm using onclick now but that feels hackish.

Answer 1

Listen for the select event on the tabpanels element:

var panels = document.getElementById("tabpanels"); // whatever your ID is
panels.addEventListener("select", function(e) {
    var el = e.target;
    alert(e.target.tagName); // tabpanels
    alert(e.target.selectedPanel) // [object XULElement] (the selected tab)
}, false);