how to open url in new tab from django?

Django is server-side, opening in a new tab is client-side. So use an <A> with a target="_blank"

http://www.google.com/search?sourceid=chrome&ie=UTF-8&q=target%3Dblank

But of course spawning new windows/tabs is annoying for the user, so try not to do that after all.

Most the time, loading the page in a new tab can be a real pain in the ar** for the user. Nevertheless it can still be necessary sometimes. If you really need to render your POST results in a new tab, use the target="_blank" as an attribute of your <form>.