Now, there are couple of ways for Flash to interact with its host page. The first one that springs to mind is getURL(), the same function that enables flash to load webpages. The second requires a little more preparation, and is ExternalInterface.call(). Both have an upside and both a downside. One's old-school and one's new-school. There are however, real reasons why you should use one instead of the other in different situations.
- The downside, from a flexibility point-of-view is that ExternalInterface can only call existing functions in either language, it can't create them on the fly. Which is more secure, I suppose.
So, to summarise:
getURL: Kills running scripts, but doesn't need a named function to exist
ExternalInterface: Doesn't kill running scripts, but does need a named function to exist