PICO-8 carts exported to HTML won't work on iOS in web app mode (a.k.a full screen web app).
Add the following meta tag to your .html file:

<meta name="apple-mobile-web-app-capable" content="yes">

Open the page in Safari iOS, add it to the homescreen, then launch it from there.

Nothing happens, the execution of PICO-8 doesn't start though it works perfectly well when launched from Safari.

The device I'm testing on, an iPhone 5, is not powerful enough to debug the web page and crashes when I try, so I don't really know what's the problem. I suspect there is a limitation blocking Emscripten somehow, maybe with the eval() function in JavaScript. I know the JIT was (is still?) disabled in webview, but the particularities of the web app mode are not documented.

It's a shame that Apple is doing their best to ruin the HTML5 experience, probably to give the priority to their closed and controlled apps ecosystem.
I'm not an iOS expert, so if you have any idea on how to fix that, please let me know.

What iOS version are you running on your phone?

I'm on the latest (v.9.3.2 or something like that).

do you have an ios ad blocker installed?

Strangely enough this is my last week working at Apple. I'll file a bug report.