Non-standard
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.
Warning: These APIs will only work in Microsoft applications, and are not on a standards track.
Microsoft browsers (Internet Explorer, and in a few cases, Microsoft Edge) support a number of special Microsoft extensions to the otherwise standard JavaScript APIs.