Pass variables into a Flash movie from HTML

Question

As a Flash newbie I found this very confusing and it cost me a couple of hours. Answering my own question here in case anyone has the same problem.

Technically you should be able to do something like this:

<param name="movie" value="movie.swf?param=value" />
<embed src="movie.swf?param=value" ...

Or this:

<PARAM NAME "FlashVars" VALUE="param=value">
<EMBED .... FlashVars="param=value">

Both should create a variable in the _root or _level0 scope called 'param' with the correct value.

These are documented here

However, in my particular version of Flash (CS4, ActionScript 2.0), this didn't work.

Answer 1

The answer which worked for me is to modify the AC_FL_RunContent() function in the HTML generated by CS4, adding the parameters which need to be passed to the movie, e.g.

'flashvars', 'param=value',

It seems this function overwrites anything which is directly specified in the OBJECT and EMBED tags or on the query string.

There may be better solutions out there...

Answer 2

You could also use ExternalInterface to call a JavaScript function on the HTML page that returns a value. This has the added value that you don't have to hardcode the value and you can pass parameters to the JavaScript function.

In the Flash Movie:

import flash.external.ExternalInterface;

function getOutsideValue(argToJS:String):Void {
 var jsArgument:String = argToJS;
 var result:Object = ExternalInterface.call("stringAdd", jsArgument);
}

In the Javascript in the HTML page:

function stringAdd(inptStr){
 var strToAdd = inptStr;
 strToAdd += " added text";
 return strToAdd;
}

So when you call the ActionScript function in Flash:

getOutsideValue("I get");

It will return:

I get added text

Note that ExternalInterface can also be used to call functions inside the Flash from JavaScript. Examples of both can be found here: http://kb2.adobe.com/cps/156/tn_15683.html

It seems that this is the recommended way to passing information to and from SWF movies, it certainly is more dynamic and powerful than just using hard coded values.