Can't view with javascript disabled. !@#$ that.
Microsoft have stopped giving a damn a long time ago, and require JS from a dozen domains just to display a bunch of text documentation.
They're definitely worse than your average JS-only website.
And yes, it's better than whatever JS is cobbled together for presentations, of course, it was designed for documents, not blinking things on the screen :)
https://en.wikipedia.org/wiki/PDF
https://en.wikipedia.org/wiki/PDF#History_and_standardizatio...