Flash :: Calculating Text Width In ActionScript And Flex?

I'm trying to calculate how WIDE to make my button, based on the text that it will contain, and when I try to google for how to calcuate something as simplistic as the WIDTH OF SOME TEXT, I go cross-eyed just trying to wade through apparently nonsensical esoteric counter-intuitive voodoo. how I would write a function like this:

public function HowWideWouldThisTextBeIfItWereInThisButton(Text:String,Container:Button):int {
...
}