Despite what people say in the comments here, both browsers really do not let you execute PDF JavaScript willy nilly. Outside of browser environments you are mostly safe anyway because JavaScript is rarely supported, with the big exception being Acrobat. The cleverness of pdftris is not so much Tetris in PDF but how it found its way around the restrictions that browser environments have put up to protect us.

From what I understand pdftris also only works because of user interaction. I think there is no way to run JavaScript in a PDF without user interaction.

(below is not serious)

I would advise people against using this in production though because it's still missing some critical features. For example:

1. The Javascript stops working when printed to physical paper. The resulting paper just has a static image and the controls no longer work.

2. It doesn't work properly in Evince. It just shows an error "The document contains only empty pages"

But there's a spec for all this and everything! https://www.t10.org/ftp/js_api_reference.pdf (2007) - be warned, the light of Ecma TC39 standardization does not extend to this place.

Chromium's implementation of setInterval for instance (which, in this world, takes a string to evaluate): https://pdfium.googlesource.com/pdfium/+/refs/heads/main/fxj... -> https://pdfium.googlesource.com/pdfium/+/refs/heads/main/fxj...

From a security perspective, they're able to build on top of V8 isolate primitives and Chrome's sandboxing systems - but from the logs, security improvements in PDFium are being continuously developed as recently as the past few weeks! I feel like I've stumbled upon a parallel universe, in the best possible way.

Took a bit of prompting but was able to get a semi-working (only in Chrome) Flappy Bird out of Claude in ~10 minutes. Seems like the collision detection needs some work :)

https://github.com/baileywjohnson/flapdfy-bird/blob/main/fla...

I don't know much about the security issues others have raised, but if you're good enough to make this thing then I deserve to be pwned by you.

Chapeau!

I am curious what the constraints are to make this work and in which environments it does? Does it work in PDF viewers outside the browser? Is there documentation what is available in which environment? What is enabled by default, can be switched on or off?

i've tried making "interactive" PDFs before but using POST and server side rendering rather than client, e.g. a PDF typewriter i made a little while back on http://news.coffee

I'm not sure what your process was for testing your scripts: but for me because there was no meaningful error output I had to incrementally build up my script line by line (which took forever.) So I thought I'd done well when I got my stuff working in Adobe + Firefox. I wonder if now everyone is going to add similar scripts to their resumes :p Doom will be next, maybe?

It doesn't work in the Adobe Chrome PDF viewer, or in Preview.

https://en.wikipedia.org/wiki/Pegasus_(spyware)#Vulnerabilit...

Something neat I found, you're able to 'clip' the blocks into each other by spinning them right before the block settles.

He never heard back from them.

Edit: here's the code for my snake game too, btw = https://github.com/robertsdotpm/resume/blob/main/snake.js

1. What led you to want to do this project?

2. Have you worked with PDFs before? Do you work with PDFs as part of your day job?

3. Have you implemented Tetris before or is this your first time?

4. How long did it take you?

Did you do the actual coding in Acrobat or is there a less painful way to write embedded JS in a PDF?

I don't do security stuff anymore but I feel chills when I see (great) things like this,

I have increasing confidence that when AIs finally destroy the Internet the delivery vehicle will be the file format that was created, as the Internet itself was, as a form of digital paper.

which is why i am commenting to check it out later.

since postscript is also a language that it literally runs to render, would it also be possible to use postscript to make interactive elements?

The .PDF basics vid was the first in the series: https://www.youtube.com/watch?v=q6KgFezu8tw

Feel much safer!