files/en-us/web/api/xrview/recommendedviewportscale/index.md
{{APIRef("WebXR Device API")}}{{SeeCompatTable}}{{SecureContext_Header}}
The read-only recommendedViewportScale property of the {{domxref("XRView")}} interface is the recommended viewport scale value that you can use for {{domxref("XRView.requestViewportScale()")}} if the user agent has such a recommendation; null otherwise.
A number greater than 0.0 and less than or equal to 1.0; or null if the user agent does not provide a recommended scale.
Dynamic viewport scaling allows applications to only use a subset of the available {{domxref("XRWebGLLayer.framebuffer", "framebuffer")}}. The feature may not be available on all systems since it depends on driver support, so you might want to ensure that {{domxref("XRView.requestViewportScale")}} exists before calling it.
for (const view of pose.views) {
if (view.requestViewportScale) {
view.requestViewportScale(view.recommendedViewportScale);
}
const viewport = glLayer.getViewport(view);
}
{{Specifications}}
{{Compat}}