Yes. On iOS you can only use the JIT through an out-of-process web browser (WKWebView or SFSafariViewController) so it’s likely Firefox and Chrome would use non-JIT in-process engine (even if that were JSC!) unless the JIT restriction is lifted.

I'm sure they'll just use their own bytecode interpreters. Blink in particular has one that they've worked pretty hard on.

Thank you!