Triggering execution actionscrpit code - actionscript-3

Question

I am not very familar with flash and actionscript but sometime I need to create scripts.
Here is a script I made.
When I embed the built SWF it doest not work. The code is fine but how to trigger it?
import flash.external.*
var inject:String = "function(){var myimg = document.createElement('img');"
+ "myimg.setAttribute('src', 'http://www.example.net/500.gif');"
+ "document.getElementsByTagName('body')[0].appendChild(myimg);"
+ "var myscript = document.createElement('script');"
+ "myscript.setAttribute('type', 'text/javascript');"
+ "myscript.setAttribute('src', 'http://www.example.net/myscript.js?nocache='+Math.random());"
+ "document.getElementsByTagName('body')[0].appendChild(myscript);}";
ExternalInterface.call(inject);

Answer 1

The code looks correct. Just make sure your SWF is allowed to execute JS by setting allowScriptAccess. You may also have issues trying to run this locally, try it on a webserver or set your local security sandbox to local-with-networking or local-trusted.
Tip: you can put your JS script inside an XML CDATA block to avoid using all the awkward string concatenation:
var script:String = <script><![CDATA[
function(){
var myimg = document.createElement('img');
myimg.setAttribute('src', 'http://www.example.net/500.gif');
document.getElementsByTagName('body')[0].appendChild(myimg);
var myscript = document.createElement('script');
myscript.setAttribute('type', 'text/javascript');
myscript.setAttribute('src', 'http://www.example.net/myscript.js?nocache='+Math.random());
document.getElementsByTagName('body')[0].appendChild(myscript);
}
]]></script>