offline, cross-tab communication (javascript-only)

Question

Is it possible to find foreign instances of certain website? Ofc theese are independently opened tabs (not by window.open). I need to prevent user from opening 2 tabs, and s

Answer 1

localStorage can be used to track windows. You should take into account a situation when window crashes - it will leave the garbage in localStorage. Accessing a common resource from several windows simultaneously may be done by mutex based on localStorage.

I've recently published the interwindow communication library (all features are described in readme). It provides thread-safe data sharing, cross-window locks and event broadcasting. It also solves some IE issues.