[Javascript] Change Extensions

[Falls, Travis D (HTSC, CASD)]

I am trying to write a javascript method that will use regular expressions
to figure out the file extension of a file name (String) and change it.
Basically I need to find ".*" and replace it with ".working"  I don't know
how to write this regular expression though.  Can someone explain how to do
this? (not just send over the regular expression I want to learn how to do
this).  Thanks.  

Travis D. Falls | Consultant   RAFT.Net   IT | 860.547.4070 |
travis.falls at thehartford.com


*************************************************************************
PRIVILEGED AND CONFIDENTIAL: This communication, including attachments, is
for the exclusive use of addressee and may contain proprietary,
confidential and/or privileged information.  If you are not the intended
recipient, any use, copying, disclosure, dissemination or distribution is
strictly prohibited.  If you are not the intended recipient, please notify
the sender immediately by return e-mail, delete this communication and
destroy all copies.
*************************************************************************