Online Army Editor was written in single javascript file. It works on unpacked *.twr file. It can be easy used on your website or to convert your web browser into offline editor.
Example embedded editor can be found here: LINK
View this page source to see the general concept.
Editor needs to know the URLs to info.xml file and units XML files. It can also contain URL to folder containing media(thumbnails).
Editor can not run the lua validation or display scripts!
Online editor passes generated army to armycalc server to validate or print it!
Unless you will pass to it a special id identifying ruleset in database on armycalc.com (this does not work for now) editor on your website would not be able to validate or generate pdf from army!