What is an alternative way to open a modal window instead of window.open?

What is an alternative way to open a modal window instead of window.open?

My Rails 3.2 application needs to be authorized against each user's
account on 3rd party website. I was using window.open to do this, but with
the different settings that are available in Internet Explorer, it was
very hit and miss and causing some user frustration.
I googled jquery modal window and basically came up with an embarrassment
of riches. Yet I haven't found a way to quite do exactly what I want. Here
are my requirements:
Open a modal child window and give it the focus.
Prevent the user from returning to the application until the child window
is closed.
The closest thing I've found is Zebra Dialog, but it appears to just have
different types of messages that you can show. I need to set the href of
the window itself so that the user can authenticate and authorize my
application for the 3rd party app user account.
Any help or pointers is greatly appreciated.