> When you open the page and it's a PDF, it gives you certain guarantees …. I think that this is a lot less true than we're used to thinking. The PDF spec con

> When you open the page and it's a PDF, it gives you certain guarantees …. I think that this is a lot less true than we're used to thinking. The PDF spec contains a lot more interactive capabilities than I think most people realise. (It supports JavaScript!) We're not used to seeing those capabilities abused, because there's no point; it is so much easier to abuse HTML. But, if people want to abuse PDF—and, if we somehow convinced the world to move to it, then they would—then they easily can. (I'm not conversant enough in the spec to know, but I do know that Postscript is Turing complete, and I don't know that PDF isn't. At least HTML on its own certainly isn't—no recursion!—although all bets go out the window once you start layering other tech on top of it.)