Offline JavaScript PubSub between browser tabs

In plain words

Offline JavaScript PubSub between browser tabs is a JavaScript library that enables communication between multiple browser tabs without requiring an internet connection. It allows developers to set up publish-subscribe messaging patterns across tabs using only offline capabilities. The tool is designed for programmers building web applications that need cross-tab coordination. It stands out by functioning entirely offline, making it useful for scenarios where tabs need to share data or events without relying on server infrastructure.

written from the facts on this page · September 2026

From the sources

TabSub offers you an easy to use Javascript PubSub via local storage. No server is required as all messages are shared via the browser built in local storage. Give the example a try to see what you can build with TabSub. Is this safe for a lot of concurrent writes? To be honest I have no clue. I tried to break it with 10 concurrent writers and everything worked as expected: No message got lost and the messages where in correct order. No warranty here, use at your own risk 😅 As TabSub uses local store this only works on the same domain, as the browser separates the local storage by domains as security measure. Start one of the two songs and than open this site in a second tab. You will see…from simon-frey.com

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