The only mandatory thing is the swf should run in the browsers that support NPRuntime.
Which almost all browsers support.

Please find the xml and AS3 Code below.

:: Download Sample

::XML

<?xml version=”1.0″ ?>
<data>
<createNamespace_js>
<script>
<![CDATA[
function(){
// Creates a global namespace called
// "Dojo" if one doesn't already exist.
// Here's one way to do this *safely*.
// If Dojo is a valid object of any type,
// including objects and functions, it will
// be left alone. If it doesn't exist, an
// exception is thrown, trapped, and
// "Dojo" is globally created.
try {
Dojo
}catch(e){
Dojo = new Object();
}
}
]]>
</script>
</createNamespace_js>
<addFunction_js>
<script>
<![CDATA[
function(){
var snafu = 'You said';
var exists = false;
// "Dojo" is a JavaScript library object
// that was created by another script,
// and exists globally.
// Just to be safe, though, we make sure
// it exists before writing to it, otherwise
// an exception is thrown.
try {
Dojo;
exists = true;
} catch(e) {
exists = false;
}

if(exists){
Dojo.myVar = 'foo';
Dojo.myFunction = function (str) {
alert(snafu + ":" + str);
}
};
}
]]>
</script>

</addFunction_js>
<callFunction_js>
<script>
<![CDATA[
function(txt, txt2){
txt = txt + " World, " + txt2;
Dojo.myFunction(txt);
}
]]>
</script>
</callFunction_js>
</data>

:: AS3

import flash.external.ExternalInterface;

var createNamespace_js:XML ;
var addFunction_js :XML ;;
var callFunction_js :XML ;;
var functionArray:Array = ["createNamespace_js","addFunction_js","callFunction_js"];

var loader:URLLoader = new URLLoader();
loader.dataFormat = URLLoaderDataFormat.TEXT;
loader.addEventListener(Event.COMPLETE, onLoadXML);

function callFunctions():void
{
// calling virtual function to create global object DOjo;
ExternalInterface.call(createNamespace_js);
// calling virtual function to add function and var to global object DOjo;
ExternalInterface.call(addFunction_js);
// calling Dojo.myFunction with 1 parameter;
ExternalInterface.call(“Dojo.myFunction”, “First call to DOjo.myFunction “);
// calling virtual function which internally alls the Dojo.myFunction ; with 2 parameters
ExternalInterface.call(callFunction_js, “Hello”, “from virtual function ” );
}

function onLoadXML(ev:Event){
try{
//Convert the downloaded text into an XML
var myXML:XML = new XML(ev.target.data)
var list:XMLList = myXML.children();
for(var i=0; i<list.length(); i++){
var temp:XML = new XML(list[i]);
for( var j in functionArray){
if(functionArray[j] == temp.name()){
this[functionArray[j]] = new XML(temp.script);
}
}
}
} catch (e:TypeError){
trace(“Could not parse the XML”)
trace(e.message)
}
callFunctions();
}
loader.load(new URLRequest(“sample.xml”));

stop()