Getting Started

Getting started with DuelJS.


With DuelJS you no need to any requirements - only vanilla js and modern web browser. Don’t try to use it with node.js without browser emulators.

Installing DuelJS

You can install it using bower or simple copy duel.js main file into your site or even clone git repository.

Different ways:

  • Bower package: bower install duel --save
  • Git repo: git clone
  • Main file: duel.min.js

Put it into your webpage: <script type="text/javascript" src="path/to/duel.min.js"></script>

So we’ve got all the set up out of the way. Let’s write some simple code.

<script type="text/javascript">
var channel ='my_first_channel');
// now you have opened some channel, this tab is connected to it

setInterval(function () {
    if (channel.currentWindowIsMaster()) {
        // here you checking is this tab active (in focus) or not
        // you can use alternative syntax: if (window.isMaster()) { ...

        document.title = 'Master ' + duel.getWindowID();
        // duel.getWindowID returns a unique browser tab id

    } else {
        document.title = 'Slave ' + duel.getWindowID();
}, 100);


When your tab had some channel (e.g. my_first_channel from previous section) you can do cross-tab broadcasting.

Use simple commands:

  • channel.broadcast(‘event_name’, a,r,g,u,m,e,n,t,s...);
    • send event command to all another tabs in channel. Alias: channel.emit.
  • channel.on(‘event_name’, function (a,r,g,u,m,e,n,t,s...) { do here what you want });
    • define watcher for event_name.
    • remove event_name watcher.
  • channel.once(‘event_name’, function (a,r,g,u,m,e,n,t,s...) { do here what you want });
    • define watcher for event_name, do it only one time and remove.