Oh, @JustinC: BTW, keep in mind that, while to do this the “easy” way requires you to do it in the page, our “target timezone” does not have to come from user input. It could be the results of a search or Some Thing’s Geographic Location’s Timezone ID, right?
So, it’s not like the user has to know what we are doing here, but we do need to get the target zone ID down to the browser.