Oh, Elm is cool. I get that. So is Haste[0].
But I think PureScript is a more practical choice for targeting JavaScript. (It generates much smaller, more readable output, for one thing.)
I don't promise to have my mind made up, though. I'm still furiously taking in all of this Haskelly stuff, and it looks like a pretty long road ahead.
I've been telling people that I feel like I've crawled into a tunnel, and can't back out again. I seem to have no choice but to keep crawling towards that tiny beam of light.
I don't know how many times I'd looked at the ML family, and just couldn't appreciate it immediately enough... but somehow I've managed to become completely obsessed, to the extent that anything less really turns my stomach.
[0] http://haste-lang.org/