XRViewport.x

The read-only XRViewport interface's x property indicates the offset from the left edge of the destination surface (typically a XRWebGLLayer to the left edge of the viewport within the surface into which WebXR content is to be rendered. The viewport's y property identifies the y component of the origin, and its is given by the width and height properties.

The offset from the left edge of the rendering surface to the left edge of the viewport, in pixels.

See the main XRViewport page for examples.