The requestReferenceSpace() method of the XRSession interface returns a promise that resolves with an instance of either XRReferenceSpace or XRBoundedReferenceSpace as appropriate given the type of reference space requested.

type

A string specifying the type of reference space for which an instance is to be returned. The string must be one of the values below.

A Promise that resolves with an XRReferenceSpace object.

The types of reference space are listed below, with brief information about their use cases and which interface is used to implement them.

bounded-floor

An XRBoundedReferenceSpace similar to the local type, except the user is not expected to move outside a predetermined boundary, given by the boundsGeometry in the returned object.

local

An XRReferenceSpace tracking space whose native origin is located near the viewer's position at the time the session was created. The exact position depends on the underlying platform and implementation. The user isn't expected to move much if at all beyond their starting position, and tracking is optimized for this use case. For devices with six degrees of freedom (6DoF) tracking, the local reference space tries to keep the origin stable relative to the environment.

local-floor

An XRReferenceSpace similar to the local type, except the starting position is placed in a safe location for the viewer to stand, where the value of the y axis is 0 at floor level. If that floor level isn't known, the user agent will estimate the floor level. If the estimated floor level is non-zero, the browser is expected to round it such a way as to avoid fingerprinting (likely to the nearest centimeter).

unbounded

An XRReferenceSpace tracking space which allows the user total freedom of movement, possibly over extremely long distances from their origin point. The viewer isn't tracked at all; tracking is optimized for stability around the user's current position, so the native origin may drift as needed to accommodate that need.

viewer

An XRReferenceSpace tracking space whose native origin tracks the viewer's position and orientation. This is used for environments in which the user can physically move around, and is supported by all instances of XRSession, both immersive and inline, though it's most useful for inline sessions. It's particularly useful when determining the distance between the viewer and an input, or when working with offset spaces. Otherwise, typically, one of the other reference space types will be used more often.

Rather than throwing true exceptions, requestReferenceSpace() rejects the returned promise with a DOMException whose name is found in the list below:

NotSupportedError

The requested reference space is not supported.