TabUtils

Multiple browser tabs communication, locking and synchronization component (same-origin). Based on localStorage object.

One small file, zero dependencies.

Features:

• Execute "interlocked" function call - runs only once across multiple tabs
• Broadcast a message to all tabs (including the current one) along with some "data" string
• ...and handle the "broadcasted message" event

Usage

<script src="https://cdn.jsdelivr.net/gh/jitbit/TabUtils/TabUtils.js"></script>

<script>

    //locked "critical section" code - runs only once
    TabUtils.CallOnce("lockname", function () { alert("I run only once in multiple tabs"); }, timeout);
    //"timeout" above is optional (for how long to hold the lock - in milliseconds)

    //handle a broadcasted message
    TabUtils.OnBroadcastMessage("eventName", function (eventDataString) { DoSomething(); });

    //sends a broadcast message to all tabs, including the current tab too!
    TabUtils.BroadcastMessageToAllTabs("eventName", eventDataString);

    //P.S. standard localStorage events are not being sent to current tab, only OTHER tabs.
    //This component sends the message to ALL tabs

</script>

Make sure you register the event handler BEFORE sending a broadcasted message.

P.S. My favorite use cases

1. Suppose you need to request something from the back end, while having multiple identical tabs open in the browser - why overwhelm the server when you can do that only once? And then send a message to other tabs

2. If you have a live websocket connection to a server (or a Server-Sent-Events connection, or even "long polling") - why keep multiple connections from indentical tabs? Keep only one and let other tabs know once something important happens. Chrome has a limit of 6 concurrent connection to a webserver when using long-polling for example. A webserver can have its own limits too.

Contributions are very welcome.

© Jitbit