Comments for Calling JavaScript from Flex (http://www.insideria.com/2009/04/calling-javascript-from-flex.html)

Calling JavaScript from Flex

2009-04-10T20:00:00Z

You might be surprised to know that Flex can create a JavaScript function and call it on the fly. For example, here is a snippet of ActionScript that shows how to obtain the URL of the page that invoked a Flex web application:

import flash.external.ExternalInterface;
var href:String;
if (ExternalInterface.available)
    href = ExternalInterface.call("function() { return location.href; }");

The page hosting the Flex application does not need to have any such function defined; the Flex application creates an anonymous function on the fly and calls it, returning the result. Most cool!

No FlashVars were harmed in the writing of this blog posting.

_______________________________

Mike Slinn
Independent full-service software contractor and author
http://slinnbooks.com
http://mslinn.com

Comment from teerasej on 2009-04-10

2009-04-11T02:12:44Z

Wow! this is very interesting! So I wonder, is it possible to call Javascript framework from this on the fly coding?

Comment from radekg on 2009-04-12

2009-04-12T13:38:55Z

@teerasej: of course it is, inside your function you can place whatever JS string you can think of. You can even load external JS on demand with document.createElement("script");

Comment from Utkal R pradhan on 2009-04-12

2009-04-13T05:43:13Z

This is already present in Curl, where you can call JavaScript functions and vice-versa !

Comment from bas on 2009-04-13

2009-04-13T09:40:47Z

There are some gotchas involved while executing code this way, especially when your javascript becomes a little more complex then the example above. We have a (commercial) product that takes care of these for you.

Thanks 4 listening!

Comment from ariel sommeria on 2009-04-14

2009-04-14T09:58:13Z

This works quite well, but not perfectly. For example it seems Internet Explorer doesn't do everything it should with ExternalInterface. I'm still digging at it...

Comment from Lars on 2009-04-19

2009-04-19T19:41:00Z

Yes, neat and useful, but I'd say it's a feature of ActionScript and Flash Player rather than Flex, the Flex framework is not required for this.

ariel sommeria, perhaps the problem you encountered in IE is the know problem for the combination of SwfObject, a Flash within a form tag and ExternalInterface calls:

http://www.google.com/search?q=externalinterface+ie+form+swfobject

Comment from alchemist on 2009-09-04

2009-09-04T22:11:07Z

Another good example of Flex Javascript interaction http://bytearray.brixtonjunkies.com/2009/08/21/flex-externalinterface-the-flex-javascript-bridge/