The System Information API

The Device APIs Working Group is currently not pursuing the approach outlined in this draft, so it should be considered historical. Please treat this document with caution and do not reference it or use it as the basis for implementation. The domain covered by this document is still within the scope of the Working Group as defined in its Charter. The Working Group may pursue an alternative API design that is based on the current Web browser security model.

This specification defines an API to provide Web applications with access to various properties of the system on which they are running. Specifically, properties pertaining to device information are exposed. Examples of such properties include battery status, current network connection characteristics, and I/O properties. Additionally, some of those properties offer access to the environment around the device, such as ambient brightness or atmospheric pressure.

API Description & Properties

System Properties

A property is defined as a set of related device characteristics. For instance, the Power property contains all the characteristics that relate to the device's electrical power supply. Properties are accessible using the functions defined by the SystemInfo interface below. A property is characterized by the following elements:

A name.
A URI, which is the concatenation of the string http://www.w3.org/2009/dap/SysInfo/ with the name of the property.
A WebIDL [[!WEBIDL]] interface that contains attributes.

The name of a property (or its URI, interchangeably) is used in the functions of the SystemInfo interface to identify the accessed property. The name of a property or its URI are equivalent for identifying the property. Character-per-character comparison will be used while matching for property, without any normalization. In response to calling one of those functions, the resulting property MUST be an instance of the property's interface i.e. an instance of the WebIDL interface that contains its attributes.

Some of the properties below are defined as enumerable, meaning that more than one instance of the property's value type exist on the system. For instance, a system with more than one hard disk would report one instance of StorageUnit for each disk. When requesting (through calls to the get() or monitor() functions) the value of an enumerable property, the success callback function will be passed an array of the property object, one for each property item. However, if an identifier is passed to the request, through the id attribute of the options parameter, then only the property object with that identifier will be returned.

The non-normative figure below illustrates the contents and relationship of all the properties defined in the following sections.

(View as SVG)

The SystemInfo interface

This interface contains the functions that enable access to the properties defined in the following sections. Objects implementing the Navigator interface (e.g. the window.navigator object) must also implement the NavigatorSystem interface [[!NAVIGATOR]]. An instance of NavigatorSystem would then be obtained by using binding-specific casting methods on an instance of Navigator.

attribute SystemInfo system: The root node from which the system information functionality can be accessed.

PendingOp get()

This function retrieves the current state of a given system property. When called, the function MUST immediately return and asynchronously acquire the current state of the requested property. If it is successful the success callback MUST be invoked and return

If this property is not enumerable, an instance of the object associated to this property.
Otherwise, an array of such instances.

For instance, requesting the property "Power" will yield an instance of the Power object, while requesting the property "StorageUnits" will return an array of StorageUnit objects, since the property is enumerable. If an error occurs, and an errorCallback function was passed to the function invocation, it is called and is passed an Error object indicating the cause of error.

DOMString propertyId: The URI or name of the property to retrieve.
SuccessCB successCallback: Function called when the properties have been successfully retrieved.
optional ErrorCB errorCallback: Function called when an error occurred while retrieving the properties.
optional Options options: An object containing the various options for fetching the property requested.

PendingOp monitor()

The monitor() function allows tracking the change of one or several system properties. When called, it immediately returns and then asynchronously starts a monitoring process defined as the following set of steps:

Acquire the system's current values for the property requested. If successful invoke the associated successCallback, passing the resulting property value an object of the type indicated by the property's value type in the definitions below. If the attempt fails, and the method was invoked with a non-null errorCallback argument, this method invokes the errorCallback, passing an ErrorCB object which reflects the cause of the error.
Register to receive system events that indicate that the status of the requested properties may have changed.
When a system event is successfully received, invoke the associated successCallback, passing an object containing the property values (or an array of such objects, if the property is enumerable). If an error occurs and the method was invoked with a non-null errorCallback argument, this method MUST invoke the errorCallback with an ErrorCB object as an argument.
Repeat the previous step until the cancel method of the PendingOp object returned by this monitor() function is invoked.

DOMString propertyId: Property URI or name identifying the property to track.
SuccessCB successCallback: Function called when the properties have been successfully retrieved.
optional ErrorCB errorCallback: Function called when an error occurred while retrieving the properties.
optional Options options: An object containing the various options for fetching the properties requested.

boolean has()

This function is used to determine if the user agent supports a specific property, whose name or URI is passed as a parameter. It MUST return true if the user agent is able to report the value of a property, and false otherwise.

DOMString propertyId: The URI or the name of the property to check.

All functions except has() return a PendingOp object, defined in [[!CORE-DEVICE]], which includes a cancel() function allowing the asynchronous operation to be stopped.

This version of the specification supports read-only access to properties. A further version may introduce read-write functionality (for instance, through as a set function) for certain properties. Examples would include screen brightness, active loudspeaker or camera aperture.

Callback interfaces

void onSuccess()

optional Object obj: The return object of a successful asynchronous operation.

void onError()

Error error: The error object of an unsuccessful asynchronous operation.

The Error interface

const unsigned short PERMISSION_DENIED = 1: The application context does not have permission to access this property.
const unsigned short INFORMATION_UNAVAILABLE = 2: The property accessed is either unknown or unavailable on this device (e.g. the battery level on a device that only has an external power source).
const unsigned short INVALID_VALUE = 3: One or more of the values in the Options object passed was invalid. For example, if the highThreshold attribute is set to a value greater than 1.0 for the CPU property.
const unsigned short TIMEOUT = 4: The length of time specified by the timeout option has elapsed before the implementation could successfully retrieve the requested property.
attribute unsigned short code: The code attribute SHOULD contain one of the error values defined in this specification. An implementation MAY define additional error codes, but those MUST NOT use the numeric values defined here.

The Options interface

attribute double highThreshold: This attribute has no effect on the get() method. On the monitor() method, it indicates that the successCallback is only be triggered if the property is a number and its value is greater than or equal this number.
attribute double lowThreshold: This attribute has no effect on the get method. On the monitor() method, it indicates that the successCallback is only be triggered if the property is a number and its value is lower than or equal this number. If both highThreshold and lowThreshold parameters are specified, the success callback is triggered if and only if the property value is either lower than the value of lowThreshold or higher than the value of highThreshold.
attribute DOMString thresholdTarget: This option specifies which attribute of the requested property is to be considered for thresholds in a monitor() operation. The value of thresholdTarget must be the name of an attribute marked as threshold target in its definition. If the value passed is not the name of an attribute that is defined as a threshold target, a user agent MUST call the error callback with the INVALID_VALUE code.
attribute unsigned long timeout: The timeout attribute denotes the maximum length of time (expressed in milliseconds) that is allowed to pass from the call to monitor() until the corresponding success callback is invoked. If the implementation is unable to successfully acquire a value before the given timeout elapses, and no other errors have occurred in this interval, then the corresponding error callback must be invoked with an Error object whose code attribute is set to TIMEOUT. Note that the time that is spent obtaining the user permission is not included in the period covered by the timeout attribute.
attribute DOMString id: In order to differentiate between instances, this attribute is used to indicate the request's target instance. The list of available identifiers would normally be retrieved first through querying the relevant property (e.g. the sources attribute of CpuState). If a property requested does not support multiple instances and an id parameter is passed, then it MUST be ignored. If a property does support multiple instances and an id parameter is passed that does not correspond to any existing instance, then the error callback MUST be called with a code set to INVALID_VALUE.

The SystemProperty interface

This interface gathers attributes shared by all properties.

attribute DOMString? info: A free-form string describing an instance of a system property, e.g. the name of a CPU manufacturer.
attribute DOMString? id: A free-form string identifying an instance of a system property. If the property is enumerable, the value of this attribute MUST be unique within the list reported in the object enumerating the device (e.g. the microphones attribute of the InputDevices property). If the instance is that of a non-enumerable property (e.g. CPU or AmbientNoise, the attribute MAY be null.

Power

The properties below expose the device's power information, either internal (battery) or external.

ECMAScript Example

// Alert the user when the power level is below 20%

if (navigator.system.has("Power"))
  navigator.system.monitor("Power",success,null,{lowThreshold:0.2, thresholdTarget:"level"});

function success(power) {
  alert("Low battery level: "+power.level);
};

The `Power` Property

This property reflects the general state of the system's power sources. The information provided when requesting this property is described by the PowerAttributes interface.

attribute float? level: Specifies how much of the internal power source remains, scaled from 0 to 100. A value of 0 indicates that the system's battery is depleted, i.e. it is about to be suspended. A value of 100 indicates that the system's charge is maximal. A value of null indicates that the API is unable to report the battery's level. Any threshold parameter used in a monitor() function to monitor this property applies to this attribute. This attribute can be used as a threshold target.
attribute unsigned long? timeRemaining: Represents the estimated time remaining in seconds before the battery will be depleted, based upon current power usage. If batteryBeingCharged is true, this value represents the estimated time remaining in seconds before the battery is depleted, based upon current power usage, if external power were removed. This attribute can be used as a threshold target.
attribute boolean isBattery: Indicates whether the current power source is a battery. This attribute must be true if the device is currently powered by a battery, and false otherwise.
attribute boolean isCharging: Indicates whether the device's battery, if in use, is currently charging. The attribute must be true if the current power source is a battery and it is being charged, and false otherwise.

CPU

This section defines interfaces that expose the system's CPU information: description and current usage information.

ECMAScript Example

//Monitor and display the CPU usage

navigator.system.monitor("CPU",success);

function success(cpu) {
  var s="CPU usage: "+cpu.usage;
  document.getElementById("cpuIndicator").innerHTML="CPU usage: "+(cpu.usage*100)+"%".
}

The `CPU` Property

This property reflects the state of the CPUs available to this system. The information provided when requesting this property is described by the CPUAttributes interface.

attribute float usage: This attribute indicates the current CPU usage, as a number between 0.0 and 1.0, representing the minimum and maximum values allowed on this system. Any threshold parameter used in a monitor() function to monitor this property applies to this attribute. This attribute can be used as a threshold target.

Thermal

The properties described in this section expose the system's temperature, as reported to the various internal thermometers.

ECMAScript Example

// Show the thermal status as an SVG analog dial

navigator.system.monitor("Thermal",success);

function success(thermal) {
  document.getElementById("GaugeHand").setAttribute("transform","rotate("+thermal.state*360+")");
};

The `Thermal` property

This property provides information on the global temperature state of the system. The information provided when requesting this property is described by the ThermalAttributes interface.

attribute float state: This attribute indicates the current thermal status, as a number between 0 and 1 representing the minimum and maximum operating values allowed by this system. On devices that have multiple thermometers, this implementation-defined value should reflect the global temperature of the system. This attribute can be used as a threshold target.

Network

These properties can be used by applications to determine the state of the network connections used by the system.

ECMAScript Example

// Find the first of the current connections that is on WiFi, and if so monitor its signal strength
navigator.system.get("Network",success,null);

function success(network) {
  var activeConnections = network.activeConnections;
  for (var i=0; i < activeConnections.length; i++) {
    var active = activeConnections[i];
    if (active.type === active.TYPE_WIFI) {
      navigator.system.monitor("Connection", {id: active.id}, wifiMonitorCB);
      // wifiMonitorCB is a user defined function that would 
      // monitor the signal strength
      break;
    }
  }
}

function wifiMonitorCB(connection) {
  document.getElementById(indicator).innerHTML = "Wireless signal at " + connection.currentSignalStrength*100 + "%";
}

The `Network` Property

This property exposes the network connections that are available on this system. The information provided when requesting this property is described by the NetworkAttributes interface.

attribute Connection activeConnections[]: The list of only network connections currently used for network access.

The `Connection` Property

This property exposes a network connection which is available on this system. The information provided when requesting this property is described by the ConnectionAttributes interface.

attribute DOMString type

The type of network connection. The value is one of

"unknown" if the type of this connection is unknown.
"ethernet" if this is an Ethernet connection.
"usb" if this is a connection over a USB port.
"wifi" if this is a Wi-Fi connection (i.e. IEEE802.11).
"wimax" if this is a WiMax connection (i.e. IEEE802.16).
"2g" if this is a 2G connection (e.g. GSM, GPRS, EDGE).
"3g" if this is a 3G connection (e.g. UMTS, CDMA).
"4g" if this is a 4G connection (e.g. LTE, UMB).

Updates of this specification may standardize more values. In the meantime vendors may define non-standard values, but must use the prefix x-.

attribute unsigned long currentDownloadBandwidth

The current real-time download bandwidth, in Kbits/s. This attribute can be used as a threshold target.

attribute unsigned long currentUploadBandwidth

The current real-time upload bandwidth, in Kbits/s. This attribute can be used as a threshold target.

attribute unsigned long maxDownloadBandwidth

This property represents the maximum download bandwidth offered by this network connection, measured in Kbits/s.

attribute unsigned long maxUploadBandwidth

This property represents the maximum upload bandwidth offered by this network connection, measured in Kbits/s.

attribute float currentSignalStrength

This connection's signal strength, as a normalized value between 0 (no signal detected) and 1 (the level is at its maximum value). This attribute can be used as a threshold target.

attribute boolean roaming

Indicates if this connection is roaming. A value of true indicates that the connection is roaming, while false indicates that it is not roaming.

Sensors

The properties defined below expose the values of external sensors, reflecting the device's environment such as temperature, ambient brightness or ambient sound.

ECMAScript Example

// Automatically adjust the UI colors if the ambient light gets too bright

navigator.system.monitor("AmbientLight",success, null, {highThreshold: 0.9, thresholdTarget:"normalizedValue"});

function success() { 
  setColorScheme('bright');  // user-defined function to set color scheme of the desktop
}

The SensorAttributes interface

The SensorAttributes interface is used as a general interface for sensor values. All the success callbacks for the properties defined in this section return an instance of this interface, with attribute values corresponding to the measurement leading to the callback being invoked.

attribute float? value: The numerical value of this sensor, at the time of sampling. Details on the meaning of the number and reported as well as its unit are given for each sensor property defined below. This attribute can be used as a threshold target.
attribute float? min: The minimum value that the sensors measuring the property are able to report.
attribute float? max: The maximum value that the sensors measuring the property are able to report.
attribute float? normalizedValue: The numerical value of this sensor, at the time of sampling, normalized on a 0 to 1 scale, where 0 represents the minimum value that the sensor can report and 1 the maximum value. This attribute can be used as a threshold target.

For an instance of SensorAttributes returned by a callback function, either value or normalizedValue can be null, but at least one MUST be non-null. normalizedValue is meant to be used when the API is not able to report a sensor value in the unit specified in this document. In that case, value stays null and normalizedValue is assigned a value which represents a unit-less measurement, between the minimum and maximum values that the device supports.

Some sensors may only be able to report two values, e.g. corresponding to "near" or "far" in the case of a proximity sensor. In that case, the normalizedValue is set to 0 for the lowest of the two values and to 1 for the greatest.

Ambient Light

The `AmbientLight` Property

This property provides information about the global level of ambient light around the device.

value represents the measured ambient light around the device, i.e. the illuminance, in lux.
min represents the minimum illuminance that the device's ambient light sensors can report, in lux.
max represents the maximum illuminance that the device's ambient light sensors can report, in lux.
normalizedValue represents the measured illuminance normalized to a 0 to 1 range.

Ambient Noise

The `AmbientNoise` property

This property provides information about the global level of ambient noise around the device.

value represents the measured ambient noise around the device, in decibels.
min represents the minimum ambient noise level that this device's sensors can report, in decibels.
max represents the maximum ambient noise level that this device's sensors can report, in decibels.
normalizedValue represents the measured ambient noise level, normalized to a 0 to 1 range.

Ambient Temperature

The `AmbientTemperature` Property

This property provides information about the temperature around the device.

value represents the measured ambient temperature around the device, in degrees Celsius.
min represents the minimum ambient temperature that this device's sensors can report, in degrees Celsius.
max represents the maximum ambient temperature that this device's sensors can report, in degrees Celsius.
normalizedValue represents the measured ambient temperature, normalized to a 0 to 1 range.

Ambient Atmospheric Pressure

The `AmbientAtmosphericPressure` Property

This property provides information about the atmospheric pressure around the device.

value represents the measured atmospheric pressure around the device, in kiloPascals.
min represents the minimum atmospheric pressure that this device's sensors can report, in kiloPascals.
max represents the maximum atmospheric pressure that this device's sensors can report, in kiloPascals.
normalizedValue represents the measured ambient temperature, normalized to a 0 to 1 range.

Proximity

The `Proximity` Property

This property provides information about the distance of objects around the device.

value represents the measured distance between the device and a nearby object, in meters.
min represents the minimum distance that this device's sensors can report, in meters.
max represents the maximum distance that this device's sensors can report, in meters.
normalizedValue represents the measured distance between the device and a nearby object, normalized to a 0 to 1 range.

Audio and Video Codecs

The properties below expose the device's audio and video codec capabilities.

ECMAScript Example

// Find if this device supports MIDI
navigator.system.get("AVCodecs",success);

function success(codecs) {
  for (var i=0;i<codecs.length;i++)
    if (codecs[i].compFormat === "MP3") {
      // ... use MP3 for encoding ...
      break;
    }
}

The `AVCodecs` property

This property exposes information about the audio/video codecs available to this system. The information provided when requesting this property is described by the AVCodecsAttributes interface.

attribute AudioCodec audioCodecs[]: The list of audio codecs available on this system.
attribute VideoCodec videoCodecs[]: The list of video codecs available on this system.

The `AudioCodec` Property

This property exposes information on a single audio codec available on this system. The information provided when requesting this property is described by the AudioCodecAttributes interface.

attribute DOMString compFormats: Space-separated list of MIME types for supported compression formats, e.g. "G.711", "MP3", "MIDI".
attribute boolean encode: true if this device supports audio encoding, false otherwise.
attribute boolean decode: true if this device supports audio decoding, false otherwise.

The `VideoCodec` Property

This property exposes information on a single video codec available on this system. The information provided when requesting this property is described by the VideoCodecAttributes interface.

attribute DOMString[] compFormats: Space-separated list of MIME types for supported compression formats, e.g. "video/x-webm", "video/ogg"
attribute DOMString[] containerFormats: Supported container format names, e.g. "AVI", "Ogg".
attribute boolean[] hwAccel;: true if the codec includes hardware acceleration support, false otherwise.
attribute DOMString[] profiles: The list of profiles available for this codec. For example, "Simple", "Main", "High" or "Advanced".
attribute DOMString[] frameTypes: The list of frame types supported by the codec. For example, "Progressive" or "Interlaced".
attribute DOMString[] rateTypes: The list of rate control options supported by the codec. For example, "CBR" or "VBR".

Storage Access

This section describe properties that expose a device's storage units, like the unit's type (hard Disk, memory card, etc.) or capacity.

ECMAScript Example

// Check each storage and warn if almost full 
            
navigator.system.get("Storage", success);
            
function success(units) {
  for (var i=0;i<units.length;i++)
    if (units[i].capacity / units[i].availableCapacity > 0.95)
      alert("Storage unit '"+units[i].info+"' almost full. You may want to free some space.");
}

The `Storage` Property

This property exposes the data storage devices connected to this system. When requested through API functions, this property returns an array of objects of type StorageUnitAttributes, corresponding to the storage devices available to this unit.

The `StorageUnit` Property

This property exposes a single data storage device connected to this system. When requested through API functions, this property returns an object of type StorageUnitAttributes, corresponding to the storage unit specified. This property is enumerable, i.e. an id parameter must be passed to the API function call to indicate which unit is requested.

The StorageUnitAttributes Interface

This interface defines the type of object returned by API functions using the Storage and StorageUnit properties.

const unsigned short TYPE_UNKNOWN=0: type is set to this value if the type of this storage unit is unknown.
const unsigned short TYPE_HARDDISK=1: type is set to this value if the device is a hard disk.
const unsigned short TYPE_FLOPPYDISK=2: type is set to this value if the device is a floppy disk.
const unsigned short TYPE_OPTICAL=3: type is set to this value if the device uses optical storage technology, e.g. CD, DVD or Holographic.
const unsigned short TYPE_FLASH=4: type is set to this value if the device uses solid-state RAM technology, e.g. chip or memory card.
attribute unsigned short type: The type of pointing device. The value is one of the constants defined for this attribute.
attribute boolean isWritable: true if this device supports software modification, else otherwise.
attribute unsigned long capacity: The amount of data that this device can hold, in bytes. A monitor() operation acting on an object of type StorageUnit must invoke the success callback only if this attribute has changed.
attribute unsigned long availableCapacity: The amount of available data that this device can hold, in bytes. This attribute can be used as a threshold target.
attribute boolean isRemoveable: true if this unit can be removed from the system (e.g. a memory card unplugged, or a disk ejected), false otherwise.

Output Devices

This section describes system properties related to this device's output devices: screens, sound systems, etc.

ECMAScript Example

// Count the screens

navigator.system.get("OutputDevices", 
                     function(devices) {
                       alert('this device has '+devices.displayDevices.length+' displays);
                     });

The `OutputDevices` Property

This property provides information on the output devices (displays or audio) available on this system. The information provided when requesting this property is described by the OutputDevicesAttributes interface.

attribute DisplayDeviceAttributes displayDevices[]: The list of display devices connected to this system.
attribute DisplayDeviceAttributes activeDisplayDevices[]: The list of display devices currently in use on this system.
attribute PrintingDeviceAttributes printingDevices[]: The list of printing devices connected to this system.
attribute PrintingDeviceAttributes activePrintingDevice: The printing device currently in use on this system.
attribute BrailleDeviceAttributes brailleDevices[]: The list of Braille terminals connected to this system.
attribute BrailleDeviceAttributes activeBrailleDevice: The Braille terminal currently in use on this system.
attribute AudioDeviceAttributes audioDevices[]: The list of audio devices connected to this system.
attribute AudioDeviceAttributes activeAudioDevices[]: The list of audio devices currently in use on this system.

The DisplayDeviceAttributes interface inherits from the Screen interface defined in [[!CSSOM-VIEW]].

const unsigned short ORIENTATION_UNKNOWN = 0: The device is not able to determine its orientation.
const unsigned short ORIENTATION_LANDSCAPE = 1: The display orientation is landscape.
const unsigned short ORIENTATION_PORTRAIT = 2: The display orientation is portrait.
const unsigned short ORIENTATION_INVERTED_LANDSCAPE = 3: The display orientation is inverted landscape.
const unsigned short ORIENTATION_INVERTED_PORTRAIT = 4: The display orientation is inverted portrait.
attribute unsigned short orientation: The display orientation from the constants listed in this object.
attribute float brightness: The current brightness, from 0 to 1.
attribute float contrast: The current contrast, from 0 to 1.
attribute boolean blanked: true if this display is currently blanked, false otherwise.
attribute unsigned long dotsPerInchW: Resolution of this device, along its width, in dots per inch.
attribute unsigned long dotsPerInchH: Resolution of this device, along its height, in dots per inch.
attribute float physicalWidth: The display's physical width in centimeters.
attribute float physicalHeight: The display's physical height in centimeters.
attribute DOMString? info: Free-form text description of the device.

The AudioDeviceAttributes interface exposes information about an audio output device available to this system.

const unsigned short TYPE_UNKNOWN=0: type is set to this value if the type of this audio device is unknown.
const unsigned short TYPE_SPEAKER=1: type is set to this value if this device is a loud speaker.
const unsigned short TYPE_HEADPHONES=2: type is set to this value if this device is a set of headphones.
attribute unsigned short type: The type of audio output device. The value is one of the constants defined for this type.
attribute unsigned long freqRangeLow: Frequency range, low value, in Hz.
attribute unsigned long freqRangeHigh: Frequency range, high value, in Hz.
attribute unsigned short volumeLevel: The volume level of a speaker, on a 0 to 100 scale.
attribute DOMString? info: Free-form text description of the device.

The PrintingDeviceAttributes interface defined below describes any device that prints text or pictures on paper.

const unsigned short TYPE_UNKNOWN=0: type is set to this value if the type of this printing device is unknown.
const unsigned short TYPE_INKJET=0: type is set to this value if this printer uses ink jet technology.
const unsigned short TYPE_LASER=1: type is set to this value if this device is a laser printer.
const unsigned short TYPE_EMBOSSED=2: type is set to this value if this device prints by carving or molding the printing surface so that the text or pictures stand out in relief.
const unsigned short TYPE_PLOTTER=3: type is set to this value if this device is a vector graphics printer.
attribute unsigned short type: The type of printer. The value is one of the constants defined for this type.
attribute unsigned long resolution: The printer's resolution, in dots per inch (dpi).
attribute boolean color: true is this printer is able to print in color, false otherwise.
attribute DOMString? info: Free-form text description of the device.

The BrailleDeviceAttributes interface describes a device for displaying Braille characters.

attribute unsigned long nbCells: The number of cells on this device.
attribute DOMString? info: Free-form text description of the device.

Input Devices

This section describes system properties related to this device's input devices: keyboards, microphones, mice, etc.

ECMAScript Example

// Check if the device supports multitouch

navigator.system.get("InputDevices", 
                     function(devices) {
                       for(var i=0; i<pointingDevices.length; i++) {
                         var pointer = pointingDevices[i];
                         if (pointer.type === pointer.TYPE_TOUCHSCREEN && pointer.supportsMultiTouch) {
                           applicationParams.hazMultiTouch = true;
                           break;
                         }
                     });

The `InputDevices` Property

This property provides information on input devices (cameras, mice) available on this system.

attribute PointerAttributes pointingDevices[]: The list of pointing devices available on this system.
attribute PointerAttributes activePointingDevices[]: The list of pointing devices available on this system that are currently in use.
attribute KeyboardAttributes keyboards[]: The list of keyboards available on this system.
attribute KeyboardAttributes activeKeyboards[]: The list of keyboards available on this system that are currently in use.
attribute CameraAttributes cameras[]: The list of cameras available on this system.
attribute CameraAttributes activeCameras[]: The list of cameras available on this system that are currently in use.
attribute MicrophoneAttributes microphones[]: The list of microphones available on this system.
attribute MicrophoneAttributes activeMicrophones[]: The list of microphones available on this system that are currently in use.

The PointerAttributes interface describes a pointing device attached to the system.

const unsigned short TYPE_UNKNOWN=0: type is set to this value if the type of this pointing device is unknown.
const unsigned short TYPE_MOUSE=1: type is set to this value if this device is a mouse.
const unsigned short TYPE_TOUCHSCREEN=2: type is set to this value if this device is a touch screen.
const unsigned short TYPE_LIGHTPEN=3: type is set to this value wen this device is a light pen.
const unsigned short TYPE_GESTURE=4: type is set to this value wen this device is a gesture device.
const unsigned short TYPE_TABLET=5: type is set to this value wen this device is a tablet.
attribute unsigned short type: The type of pointing device. The value is one of the constants defined for this type.
attribute boolean supportsMultiTouch: true if this device supports the multi-touch method of interaction, else otherwise.
attribute DOMString? info: Free-form text description of the device.

The KeyboardAttributes interface describes a keyboard or keypads attached to this system.

const unsigned short TYPE_UNKNOWN=0: type is set to this value if the type of this keyboard is unknown.
const unsigned short TYPE_KEYBOARD=1: type is set to this value if this device is a full keyboard.
const unsigned short TYPE_KEYPAD=2: type is set to this value if this device is a keypad.
attribute unsigned short type: The type of pointing device. The value is one of the constants defined for this type.
attribute boolean isHardware: true if this device is a physical keyboard, else if it is a software keyboard.
attribute DOMString? info: Free-form text description of the device.

The CameraAttributes interface property describes a camera or similar video capture device connected to this system.

attribute boolean supportsVideo: true if this device supports recording video, else otherwise.
attribute boolean hasFlash: true if this device supports has a flash, else otherwise.
attribute unsigned long sensorPixels: The number of picture elements (pixels) of this camera.
attribute float? maxZoomFactor: The maximum zoom factor of this camera. This value MUST be null if the camera does not have a zoom (whether physical or digital).; Name of the camera (suitable for use as a ;source=name type parameter in input elements for forms; Space-separated list of available MIME types such as "image/png video/x-webm ..."

The MicrophoneAttributes interface describes a microphone or similar audio capture device attached to the system.

const unsigned short TYPE_UNKNOWN=0: type is set to this value if the type of this microphone is unknown to this API.
const unsigned short TYPE_MICROPHONE=1: type is set to this value if this device is a microphone.
const unsigned short TYPE_LINEIN=2: type is set to this value if this device is a line-in connector.
attribute unsigned short type: The type of audio input device. The value is one of the constants defined for this type.
attribute unsigned long freqRangeLow: Frequency range, low value, in Hz.
attribute unsigned long freqRangeHigh: Frequency range, high value, in Hz.
attribute DOMString? info: Free-form text description of the device.
attribute DOMString? name: Name of the microphone, such as "microphone", "camcorder", "webcam", or "line-in" (suitable for use as a ;source=name type parameter in input elements for forms, e.g., input type=file accept="audio/x-speex;quality=7;bitrate=16000;source=webcam"
attribute DOMString[] types: Space-separated list of available MIME types such as "audio/x-speex audio/ogg"

Mapping to the W3C Delivery Context Ontology

The table below lists each interface or attribute described in this specification, as well as the corresponding classes or properties from [[DCONTOLOGY]], if it exists.

System Information	Delivery Context Ontology	Notes
Power
`PowerAttributes.level`	`hard:batteryLevel`
`PowerAttributes.timeRemaining`
`PowerAttributes.isExternal`
`PowerAttributes.batteryBeingCharged`	`hard:batteryBeingCharged`
CPU
`CPUAttributes.usage`
Thermal
`ThermalAttributes.state`
Network
`NetworkAttributes.activeConnections`
`ConnectionAttributes.currentDownloadBandwidth`
`ConnectionAttributes.currentUploadBandwidth`
`ConnectionAttributes.maxDownloadBandwidth`
`ConnectionAttributes.maxUploadBandwidth`
`ConnectionAttributes.minDownloadBandwidth`
`ConnectionAttributes.minUploadBandwidth`
`ConnectionAttributes.currentSignalStrength`
`ConnectionAttributes.roaming`
SensorAttributes
`SensorAttributes.value`
`SensorAttributes.min`
`SensorAttributes.max`
`SensorAttributes.normalizedValue`
Codecs
`AVCodecsAtributes.audioCodecs`
`AVCodecsAttributes.videoCodecs`
`AudioCodecAttributes.compFormat`
`AudioCodecAttributes.encode`
`AudioCodecAttributes.decode`
`VideoCodecAttributes.compFormats`
`VideoCodecAttributes.containerFormats`
`VideoCodecAttributes.hwAccel`
`VideoCodecAttributes.profiles`
`VideoCodecAttributes.frameTypes`
`VideoCodecAttributes.rateTypes`
Storage
`StorageUnitAttributes.type`
`StorageUnitAttributes.isWritable`
`StorageUnitAttributes.capacity`
`StorageUnitAttributes.availableCapacity`
`StorageUnitAttributes.isRemoveable`
Output Devices
`OutputDevicesAttributes.displayDevices`
`OutputDevicesAttributes.activeDisplayDevices`
`OutputDevicesAttributes.audioDevices`
`OutputDevicesAttributes.activeAudioDevices`
`DisplayAttributes.orientation`
`DisplayAttributes.brightness`
`DisplayAttributes.contrast`
`DisplayAttributes.blanked`
`DisplayAttributes.dotsPerInchW`
`DisplayAttributes.dotsPerInchH`
`DisplayAttributes.physicalWidth`
`DisplayAttributes.physicalHeight`
`SpeakerAttributes.type`
`SpeakerAttributes.freqRangeLow`
`SpeakerAttributes.freqRangeHigh`
`SpeakerAttributes.volumeLevel`	`hard:volumeLevel`
Input Devices
`InputDevicesAttributes.pointingDevices`
`InputDevicesAttributes.activePointingDevices`
`InputDevicesAttributes.keyboards`
`InputDevicesAttributes.activeKeyboards`
`InputDevicesAttributes.cameras`
`InputDevicesAttributes.activeCameras`
`InputDevicesAttributes.microphones`
`InputDevicesAttributes.activeMicrophones`
`PointingDeviceAttributes.type`
`PointingDeviceAttributes.supportsMultiTouch`	[[DCONTOLOGY]] has `hard:tactileDisplay` but only covers touchScreen, mice and styluses are normative instances of `hard:inputDevice`
`KeyboardAttributes.type`
`KeyboardisHardware`
`CameraAttributes.supportsVideo`
`CameraAttributes.sensorPixels`
`CameraAttributes.hasFlash`
`CameraAttributes.maxZoomFactors`
`MicrophoneAttributes.type`
`MicrophoneAttributes.freqRangeLow`
`MicrophoneAttributes.freqRangeHigh`

Property	Property Interface	Attributes
`Power`	`PowerAttributes`	`level timeRemaining isBattery isCharging`
`CPU`	`CPUAttributes`	`usage`
`Thermal`	`ThermalAttributes`	`state`
`Network`	`NetworkAttributes`	`activeConnections`
`Connection`	`ConnectionAttributes`	`type currentDownloadBandwidth currentUploadBandwidth maxDownloadBandwidth maxUploadBandwidth currentSignalStrength roaming`
`AmbientLight AmbientNoise AmbientTemperature AmbientAtmosphericPressure Proximity`	`SensorAttributes`	`value min max normalizedValue`
`AVCodecs`	`AVCodecsAttributes`	`audioCodecs videoCodecs`
`AudioCodec`	`AudioCodecAttributes`	`compFormat encode decode`
`VideoCodec`	`VideoCodecAttributes`	`compFormats containerFormats hwAccel profiles frameTypes rateTypes`
`Storage`	`StorageUnitAttributes (array)`
`StorageUnit`	`StorageUnitAttributes`	`type isWritable capacity availableCapacity isRemoveable`
`OutputDevices`	`OutputDevicesAttributes`	`displayDevices activeDisplayDevices printingDevices activePrintingDevices brailleDevices activeBrailleDevices audioDevices activeAudioDevices`
	`DisplayDeviceAttributes`	`orientation brightness contrast blanked dotsPerInchW dotsPerInchH physicalWidth physicalHeight info`
	`AudioDeviceAttributes`	`type freqRangeLow freqRangeHigh volumeLevel info`
	`PrintingDeviceAttributes`	`type resolution color info`
	`BrailleDeviceAttributes`	`nbCells info`
`InputDevices`	`InputDevicesAttributes`	`pointingDevices activePointingDevices keyboards activeKeyboards cameras activeCameras microphones activeMicrophones`
	`PointerAttributes`	`type supportsMultiTouch info`
	`KeyboardAttributes`	`type isHardware info`
	`CameraAttributes`	`supportsVideo hasFlash sensorPixels maxZoomFactor`
	`MicrophoneAttributes`	`type freqRangeLow freqRangeHigh info`

Introduction

Security and Privacy Considerations

Privacy considerations for implementors of the System Info API

Additional implementation considerations

API Description & Properties

System Properties

The SystemInfo interface

Callback interfaces

The Error interface

The Options interface

The SystemProperty interface

Power

ECMAScript Example

The Power Property

CPU

ECMAScript Example

The CPU Property

Thermal

ECMAScript Example

The Thermal property

Network

ECMAScript Example

The Network Property

The Connection Property

Sensors

ECMAScript Example

The SensorAttributes interface

Ambient Light

The AmbientLight Property

Ambient Noise

The AmbientNoise property

Ambient Temperature

The AmbientTemperature Property

Ambient Atmospheric Pressure

The AmbientAtmosphericPressure Property

Proximity

The Proximity Property

Audio and Video Codecs

ECMAScript Example

The AVCodecs property

The AudioCodec Property

The VideoCodec Property

Storage Access

ECMAScript Example

The Storage Property

The StorageUnit Property

The StorageUnitAttributes Interface

Output Devices

ECMAScript Example

The OutputDevices Property

Input Devices

ECMAScript Example

The InputDevices Property

Extensibility

Mapping to the W3C Delivery Context Ontology

Properties And Attributes Table

Acknowledgements

The `Power` Property

The `CPU` Property

The `Thermal` property

The `Network` Property

The `Connection` Property

The `AmbientLight` Property

The `AmbientNoise` property

The `AmbientTemperature` Property

The `AmbientAtmosphericPressure` Property

The `Proximity` Property

The `AVCodecs` property

The `AudioCodec` Property

The `VideoCodec` Property

The `Storage` Property

The `StorageUnit` Property

The `OutputDevices` Property

The `InputDevices` Property