Why does Flash's ExternalInterface *sometimes* not work?

Question

I have a Flash movie which has a number of actionscript 2 functions which are exposed to Javascript via ExternalInterface. Normally this movie works fine and Javascript can communicate with it. But sometimes, intermittently and without explanation, the flash object in Javascript will not have the ExternalInterface functions. This happens when I have this single flash file installed on the page more than once, and it often happens that one or two instances of the flash will have the functions, and one or two will not. Same exact flash source, embedded onto the page 3 or 4 times. Very odd. Any ideas as to what might be wrong or even where I should start looking? I am at a loss.

Answer 1

Maybe you problem is that the Flash app is not ready when you make the call.

Whenever I had to do communication JS > Flash I always let Flash "do the talking". Basically, enable a JS function that the Flash movie calls when it's ready and fully loaded. Then and only then allow the JS side to make calls to Flash.

HTH!

Juan