App Development API Reference

The following is a list of code-level reference documentation you'll likely need in developing a Firefox OS app. For lightning-fast search and browsing of Web APIs and methods, try dochub.io, a site that uses MDN's API to provide a rapid lookup of almost every feature the Web platform has to offer.

Note: The technologies detailed below should work across modern browsers; notes are included below to indicate where this differs.

Note: For a granular, detailed account of what new features have been added in what Firefox OS releases, consult our Firefox OS release notes.

Foundations of a Firefox OS app

A Firefox OS app is simply an Open Web App, but with extra features available such as being installable, and access to device APIs to control hardware and device features such as contacts, alarms, etc.

App manifest: The manifest describes your app. This guide explains how the manifest works and how to create one.
App Installation and Management APIs: The programmatic interface you use for installing apps and managing them.
Working offline: Strategies and technologies you can use to ensure that your app works when there's no network connection available.
Types of apps: This article explains the types of apps: hosted, privileged, and certified. You need privileged or certified apps for access to sensitive device APIs. Privileged and certified apps are packaged apps.
App permissions: Access to device APIs is key to creating many useful apps. Here is what's available and how to access them.

Layout and structure

The building blocks of responsive design: Learn the basics of responsive design, an essential topic for modern app layout.
Media queries: One of the most important technologies in responsive app design is the media query. Media queries allow your app to respond to screen size, resolution, device orientation, and many other environment variables using declarative CSS rules or JavaScript listeners. Also see Using media queries and MediaQueryList.
Mobile first: Often when creating responsive application layouts, it makes sense to create the mobile layout as the default, and build wider layouts on top.
Flexible boxes: CSS flexible boxes let you configure your app's user interface to automatically adjust the positioning and sizes of elements based on the size and orientation of the display.

Note: If you are developing Firefox OS apps, be aware that multi-line flexboxes are supported in Firefox OS 1.3+; for older versions you might have to adopt a simpler layout or provide a fallback.

Drawing and animation

CSS transforms: CSS transforms let you rotate, scale, and zoom HTML content, taking advantage of hardware acceleration where available, all without relying on JavaScript code.
CSS transitions: CSS transitions let you animate changes to your CSS. Once a transition effect is configured, changes to your CSS occur over a period of time instead of instantaneously. This makes it possible to easily and efficiently create a wide variety of visual effects in your apps.
CSS animations: CSS animations let you animate changes to your document on a more fundamental level, using keyframes to precisely configure the animation effect. This also lets you create looping animation effects rather than effects that happen just once, as is the case with transitions, all without relying on JavaScript.
HTML canvas: The HTML <canvas> element provides a 2D graphics workspace for you to draw in. This has many uses, including 2D games.
WebGL: WebGL is a Web-friendly version of OpenGL ES that lets your app offer hardware-accelerated 3D graphics.
SVG: Scalable Vector Graphics (SVG) is a technology that lets you draw graphics using vectors instead of bitmapped images. This is great for scalability, presenting diagrams and charts, and for high-quality, scalable user interfaces.

Firefox OS device APIs

These are emerging Web platform standards and device APIs crucial to Firefox OS app development and to Open Web Apps.

The following table gives the app manifest permissions for hosted and privileged apps. For more information see App permissions.

Manifest permission	API name	Description	Minimum app type required	`access` property	Default granted	Platform/version supported
`alarms`	Alarm	Schedule a notification, or schedule an application to be started.	hosted	none	`Allow`	FxOS 1.0.1
`audio-capture`	GetUserMedia	Obtain `MediaStream` from audio input devices, e.g. microphone. This is needed to allow audio capture in Firefox OS 1.2+.	hosted	none	`Prompt` for all installed App types.	FxOS 1.2 for audio Desktop Firefox 20+
`audio-channel-alarm`	AudioChannels	Alarm clock, calendar alarms.	privileged	none	`Allow`	FxOS 1.0.1
`audio-channel-content`	AudioChannels	Music, video.	hosted	none	`Allow`	FxOS 1.0.1
`audio-channel-normal`	AudioChannels	UI sounds, Web content, music, radio.	hosted	none	`Allow`	FxOS 1.0.1
`audio-channel-notification`	AudioChannels	New email, incoming SMS.	privileged	none	`Allow`	FxOS 1.0.1
`browser`	Browser	Enables the app to implement a browser in an `iframe`.	privileged	none	`Allow`	FxOS 1.0.1
`camera`	Camera	Take photos, shoot video, record audio, and control the camera. Note: `camera` was limited to certified apps initially because the app sandbox was preventing access to the camera hardware. Fixed from Firefox OS 2.0 onwards.	privileged in Firefox OS 2.0+ internal/certified up to Firefox OS 1.4	none	`Prompt` for all installed App types.	FxOS 1.0.1-1.4 certified FxOS 2.0+ privileged
`contacts`	Contacts	Add, read, or modify contacts from the address book on the device and read contacts from the SIM.	privileged	`readonly`, `readwrite`, `readcreate`, or `createonly`	`Prompt` for all installed App types.	FxOS 1.1 Firefox Android 18
`desktop-notification`	mozNotification for Gecko <22, Notification for Gecko 22+	Display a notification on the user's desktop. Note that this has changed, so for Gecko <22 (Firefox OS <1.2) you need to use `mozNotification`, while for Gecko 22+ (Firefox 1.2+) you need to use `Notification`.	hosted	none	`Prompt` for Web content. `Allow` for all installed App types.	FxOS 1.0.1, Android 4.0, Desktop 4.0 for prefixed version FxOS 1.2, Android 22, Desktop 22 for non-prefixed version
`device-storage:music`	Device Storage	Add, read, or modify music files stored on the device.	privileged	`readonly`, `readwrite`, `readcreate`, or `createonly`	`Prompt`	FxOS 1.0.1
`device-storage:pictures`	Device Storage	Add, read, or modify picture files stored on the device.	privileged	`readonly`, `readwrite`, `readcreate`, or `createonly`	`Prompt`	FxOS 1.0.1
`device-storage:sdcard`	Device Storage	Add, read, or modify files stored on the device's SD card.	privileged	`readonly`, `readwrite`, `readcreate`, or `createonly`	`Prompt`	FxOS 1.0.1
`device-storage:videos`	Device Storage	Add, read, or modify video files stored on the device.	privileged	`readonly`, `readwrite`, `readcreate`, or `createonly`	`Prompt`	FxOS 1.0.1
`fmradio`	FM Radio	Control the FM radio.	hosted	none	`Allow`	FxOS 1.0.1
`geolocation`	Geolocation	Obtain the current location of the user.	hosted	none	`Prompt` (even for certified Apps)	FxOS 1.0.1, Desktop Firefox 3.5, Android 4.0
`input`	Keyboard	Allows the app to act as a virtual keyboard by listening to focus change events in other apps.	privileged	none	`Allow`	FxOS 1.0.1
`mobileid`	Mobile identity	Allows an app to obtain a verified phone number (MSISDN) after the user selects the number to be shared and gives explicit permission for the app to obtain it.	privileged/	none	`Prompt`	FxOS 2.0
`mobilenetwork`	Mobile Network	Obtain mobile network information (MCC, MNC, etc.).	privileged	none	`Allow`	FxOS 1.0.1
`moz-firefox-accounts`	Firefox Accounts	Allows the use of Firefox Accounts when using the navigator.mozId API.	privileged	none	`Prompt` for all installed App types.	FxOS 2.0
`nfc`	NFC API	Enable an app to transmit data to other devices via near field communication.	internal (certified) from FxOS 2.0 privileged from FxOS 2.2	none	`Allow`	FxOS 2.0
`push`	Simple Push	Enable an app to wake up to receive notification.	hosted	none	`Allow`	FxOS 1.1
`storage`	Storage	Utilize storage (appcache, pinned apps, IndexedDB) without size limitations. See appcache, IndexedDB.	hosted	none	`Allow`	FxOS 1.0.1, Desktop (early versions)
`systemXHR`	SystemXHR	Allows anonymous (no cookies) cross-origin XHR without the target site having CORS enabled. Similar to the TCP Socket API but restricted to XHR, not just raw sockets, so it is slightly less risky. See XMLHttpRequest.	privileged	none	`Allow`	FxOS 1.0.1
`tcp-socket`	TCP Socket	Create TCP sockets and communicate over them.	privileged	none	`Allow`	FxOS 1.0.1, Desktop (early versions)
`video-capture`	GetUserMedia	Obtain MediaStream from video input devices, e.g. camera. This is needed to allow video capture in Firefox OS 1.4+.	hosted	none	`Prompt` for all installed App types.	FxOS 1.4

Note: To declare an app as privileged, you need to put "type" : "privileged" into your app manifest. You don't need to include the type field in your manifest for web apps, as web is the default value.

General Web APIs

Elements, events, network requests, storage and other standard Web APIs

Network requests - send and receive data with XMLHttpRequest

XMLHttpRequest is the DOM API used to send and receive information using HTTP, including for downloading files.

DOM events

The event reference provides a complete list of all the events that can be sent and received to interact with DOM objects.

Touch events

This documentation covers touch events in particular, which of course you are likely to encounter when developing apps for touchscreen devices.

Online & offline events

Allows your app to dynamically respond to changes in network connection availability.

History

Travers and manipulate the historical view state of your app with various commands - helpful in rewinding or advancing the user's current view

Audio

Embedding and manipulation of audio content with the HTML5 Audio Tag

Video

Embedding and manipulation of video content with the HTML5 Video Tag

Geolocation

Enables your app to request the user's current location and listen for location changes.

Screen orientation

Listen for high-level screen orentation changes between various portrait and landscape positions.

Device orientation

Allows your app to detect granular device orientation changes from on-device sensors.

IndexedDB

A database access layer for Web apps that provides a scriptable interface for storing and retrieving large sets of data on the user's device.

Storage

The Storage API family provides various way to persistently store limited amounts of simple data on a user's device.

localStorage
sessionStorage
Blob - An object that represents a file-like object of immutable, raw data. The data contained can be manipulated and mutated into several common formats (images, etc).

Web workers

Allows apps to run JavaScript code (which cannot touch the DOM or window object) in background threads to optimize performance and unblock UI rendering

Firefox Marketplace services

These documents and guides will help you learn how to publish your app and manage it on the Firefox Marketplace.

Submission API: The Submission API lets you validate your app, update your app, and fetch information about the apps available to be installed.
Marketplace API: All Marketplace-related documentation is centered here.