racketscript VS SinScheme

I don't think there's any mature projects that compile to WASM yet, but there's been some steady progress on that front. There's also a dialect of Racket that transpiles to Javascript and a #lang that lets you write Javascript using Racket syntax.

The github page has more information: https://github.com/racketscript/racketscript

And to answer the questions every Schemer will have, no the runtime doesn't yet support tail calls or continuations.

You can use Racket in the browser with RacketScript

https://github.com/racketscript/racketscript It's still labeled experimental but in much the same way that Gmail is still technically in beta.

You could try Racket on the client side…with RacketScript: https://github.com/racketscript/racketscript

For example: SinScheme has an llvm-convert module which converts compiled S-expressions into LLVM IR.

Heres a small compiler from a Scheme subset to LLVM. I hand-emit the LLVM IR, in lieu of libraries.

In my Scheme->LLVM compiler, I have a pass closure-convert which makes all closures explicit, and strays from a strict lisp syntax to a more c-like style. Then in my llvm-convert pass, I convert the proc language into LLVM.