I'm not sure if it's possible, but why would you want it anyway? A user is unlikely to visit your website using two different browsers.
Thanks dmjpro,acoder
well i am working on behavioral targeting
and if the user comes across a website using different browsers at different times, then the value stored in cookie should be read and updated and if it is not possible in cross browsers then the user will have more than one user id, one for browser a and another for browser b and so on
if cross browser cookie can be implemented, i can track users across different browsers so thats why i was asking for this