Retrieve a list of browsers/agents installed in client system
You cannot do this unless you have some signed control installed on the client computer; or have them download a program which runs (separate from a browser) and sends the information to your server, where your django app can access it.
This is not possible using javascript (as it runs in a sandbox).
I would like to write a web application (in django) which scans the client/remote computers (assumption is windows) and retrieve the list of software's(mainly browsers) installed. Looking for suggestions to implement it.

Is this possible without asking the user to download any scritps/exe's?
If so, is it possible via java script?

I am planning to use python/django to write the entire app. Any input would be much appreciated.
EDIT : Comments on feasibility in java also much appreciated