I've tried working with selectedIndex, selectedItem and selectedTab but
can't seem to get anything beyond "undefined."
https://developer.mozilla.org/en/Code_snippets/Tabbed_browser
Refer to 'Reusing by other criteria' section. This might do the trick
for you.
var tabs = document.getElementById("TabList");
if( tabs.selectedIndex == 0 ) {
alert("Tab A Selected");
} else {
alert("Tab B Selected");
}
Again, thanks for the push in the right direction.