I'm not sure what other language you could use to add client-side functionality to a static webpage? But anyway, if you want to avoid a compilation step, the l

I'm not sure what other language you could use to add client-side functionality to a static webpage? But anyway, if you want to avoid a compilation step, the link GP mentioned shows how TypeScript can check JS files annotated with normal comments. You can run it through the a compiler to remove the annotations if you want, but it's absolutely not required.