Retrieve the URL from swf

I am having problems with the _url property

I need to retrieve the url from where my swf is located and not the url for the swf.

How can i do this?

The prob is that i have a swf that will do this job in a url:

When getting the _url property on it it always traces
and not

How can i make it trace the url that is in the browser and not the url for the swf?