[Arch-TK]

It takes less time to write the prompt, you could just publish that?

It's an important topic, and I am glad you wrote about it, but even half a page of notes would have been enough to convey this. It would save me literally skim reading headings just to get past all the fluff.

[rootusrootus]

Isn’t “just post the prompt” a joke? That only works if the content was one-shot, and I bet that (much like code) most isn’t.

[Arch-TK]

I didn't mean it completely literally. But presumably you have an idea for a post outline:

* Title

* Brief

* Table showing the issue

* Notes about CSS/JS disparity

* An idea for why it happens.

* The idea/code for a solution.

This could just be:

Chromium allows websites to figure out your OS using math functions

Chromium's implementation of Math.tanh and CSS trigonometry functions since version 148 uses the host libc implementation. This is a problem because libc implementations vary between operating systems and can produce slightly different results on different platforms (and potentially even different versions of the same platform). This can be used to accurately distinguish between Linux, MacOS and Windows.

Here's a table showing the issue with Math.tanh:

...

For javascript, so far it's only Math.tanh that uses the system libc, the rest of the functions are implemented in V8. But for CSS it's worse, all functions use the libc versions.

Since math should be deterministic, it would be an improvement to privacy as well as platform uniformity to have V8 implement tanh and have the CSS use those implementations too. <side>Notably there are also some quirks in Web Audio. ...</side>

Here's some code which when compiled with `-ffp-contract=off` will produce the same MacOS result on all the other platforms Chromium supports. One option is to just unify the results, another is to make them match the claimed platform.

...

---

It took me 10 minutes to draft the above. With the effort it probably took to prompt that blog post, you could probably get it proofread, generate the table if you have access to the right boxes but don't have it already. And produce the right code with a test harness, verify it.

It's a lot shorter, but that's because the post doesn't really have that much content. There's huge quantities of fluff, the entire "Four Traps" section is so incoherent that I still don't get what it's trying to say after trying to read it 4 times on two different occasions.