Detecting Mozilla App Install Capabilities with JavaScript

If you follow me on Twitter, you know I'm riveting super excited about the forthcoming Firefox Marketplace. A marketplace where you can download desktop, tablet, and mobile phone applications based on web technologies, from a host with a record as awesome as Mozilla, is a dream come true. The initial install process is powered via a JavaScript interface within Firefox, and if you can detect if the user's current Firefox install has app capabilities, you can advertise your own app when they come to your website.

The JavaScript

Feature detection is the best way to discover if the user's browser can install Firefox Marketplace applications:

var canInstallMozApp = !!(navigator.mozApps && navigator.mozApps.install);

Marketplace features live within the navigator object under the mozApps property. The install method triggers app installation, so that's ultimately the method whose existence should be checked. If present, the user has app install capabilities and you know you can show a "download our app" advertisement or, if your app manifest is configured properly, you can install the app from your own site!