Abstract: Many tools allow programmers to develop applications in high-level languages and deploy them in web browsers via compilation to JS. While practical and widely used, these compilers are ad hoc: no guarantee is provided on their correctness for whole programs, nor their security for programs executed within arbitrary JS contexts. This paper presents a compiler with such guarantees. We compile an ML-like language with higher-order functions and references to JS, while preserving all source program properties. Relying on type-based invariants and applicative bisimilarity, we show full abstraction: two programs are equivalent in all source contexts if and only if their wrapped translations are equivalent in all JS contexts. We evaluate our compiler on sample programs, including a series of secure libraries.