This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.
The non-standard and internal only
CanvasRenderingContext2D.drawWidgetAsOnScreen() method of
the Canvas 2D API renders the root widget of a window into the canvas. Unlike
drawWindow(), this API uses the
operating system to snapshot the widget on-screen, rather than reading from Gecko's own
This API cannot be used by Web content. It is only supported on Windows, only on widgets that use OMTC, and only from within the chrome process.
Not part of any current specification or draft. This is a non-standard and internal only API.
BCD tables only load in the browser