Javascript library for ensuring that important things happen in just one tab.

Some apps need things to happen in exactly one tab. Or, at the very least, it would be a nice thing to have.

Use it when your app...

• Plays music and shouldn't play a bunch of things at once! (like Soundcloud)
• Writes to local files (lock contention, etc).
• Is a multiplayer game and should only have one person per computer
• Fights with itself and needs to be kept in line.

The contents of this repo are more or less hosted on my own site here. Try it out by opening it in a few tabs and pressing the "on" and "off" buttons. Alternately, pull the repo and host it somewhere.

For some reason, localStorage events don't trigger properly on file:// urls, so it does need to be hosted (or, at least this is what I've noticed in Chrome).

Source it in your html:

<script type="text/javascript" src="path/to/tab.js"></script>

And that's it.

Oh, and there are no dependencies aside from localStorage support. So that's kinda cool, I guess.

Initialize a tab object in any page you want to track.

var tab = new Tab({
  on: function()  { alert("on!");  },
  off: function() { alert("off!"); }
});

By default, on and off are empty functions. You could initialize a bunch of tabs and have them do nothing. But that's silly.

Turning a tab on turns all other tabs off, and can be done as such:

tab.on();

Manually turning a tab off is similar:

tab.off();

The Tab() object takes in an object that specifies the functions to call when on and off events are triggered, and supports a number of options. Here are their defaults:

var tab = new Tab({

	/* Code you only want to happen in one tab */
	on: function() {},
	
	/* Code to do when a tab is done being on */
	off: function() {},

	/* Trigger on without waiting for other tabs to turn off */
	force: false

});

An instance of the Tab() object supports a number of methods:

/* Turn a tab on. Pass in args to your supplied method, although this doesn't
 * do anything for now. Force is a string and can either be "off" or "on". 
 */
tab.on([args, force]); 

/* Turns a tab off. Again, pass it arguments if you'd like. Nothing to force
 * here, though. 
 */ 
tab.off([args]);

/* Get the current status of a tab. Returns true if on, false otherwise. 
 */ 
tab.status();

/* Show the tab's id. */
tab.id;

• Implement tab identifiers so multiple tab groups can exist across browsers. Something like group : [group_name].
• Pass arguments to on and off.
• Bug fixing (for some reason, on() needs to be called twice. Not ok).