Why use DoFSCommand if one can just getUrl?

I read it's possible to c开发者_开发知识库all any javascript http://scriptplayground.com/tutorials/as/Call-Javascript-in-Flash/

so why would I need doFscommand ?

fscommand() was the only option to communicate between flash and javascript before External Interface was introduced.

more here: http://kb2.adobe.com/cps/141/tn_14192.html#main_main_externalinterface