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Comment by alexis_fr | Hacker News Reader

This French startup claims it is able to run some Javascript in the PDF, therefore notify you when a customer reads your offer, tell you which part he read, where he stayed the longest, etc. Does PDF support JS?

https://www.tilkee.com/

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Yup. If you open this PDF in Chrome, you can even play Breakout:

https://rawgit.com/osnr/horrifying-pdf-experiments/master/br...

That's creepy and makes me glad I don't use Chrome (doesn't work in Firefox).

You can run JS in a PDF. You can even embed Flash in a PDF. We tend to think as PDFs as an innocuous document format, but there's a lot more than that baked in.

Adobe actually offers "features" like readership tracking in PDFs as part of their commercial offerings.

Thankfully about half the "features" of PDF like js tracking and restrictions on editing or printing are ignored by almost every PDF reader not made by adobe.

Strongly considering pulling Acrobat company wide and replacing with something like FoxIt.

Last time I opened PDF with JS even Acrobat warned about that and disabled it by default (but that was some time ago).

Wow, yikes, you CAN run Javascript in a PDF:

https://www.adobe.com/devnet/acrobat.html

Horrible but not terribly surprising.

I’ve been told the PDF spec has some low level functionally to support a MS-DOS emulator. Don’t know how true that is.

You bet it does! https://pspdfkit.com/blog/2018/how-to-program-a-calculator-p...

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