We present a way to run Objective Caml programs on a standard, unmodified web browser, with a compatible data representation and execution model, including concurrency. To achieve this, we designed a byte-code interpreter in JavaScript, as well as an implementation of the run-time library. Since the Web browser does not provide the same interaction mechanisms as a typical Objective Caml environment, we provide an add-on to the standard library, enabling interaction with the Web page. As a result, one can now build the client side of a web application with the standard Objective Caml compiler and run it on any modern web browser. Categories and Subject Descriptors D.3.3 [Programming Languages]: Language Constructs and Features; D.3.4 [Programming Languages]: Run-time environments; H.5.3 [Information interfaces and presentation]: Web-based interaction General Terms Languages, Design, Experimentation Keywords Virtual machine, Web browsers, Objective Caml, Document Object Model, JavaScrip...