We present an online environment for the design of musical scores, also allowing for the embedding of signal processors and hence the publication of electronic works. This environment is part of the INScore project. Its latest version has been transcribed to WebAssembly/Javascript to provide in a web browser the same features as in its native counterpart: the diversity of music representations supported by INScore, the interaction capabilities and all the dynamic aspects of the score. After some historical elements about distributed musical scores, we will provide some reminders about the INScore project and its associated description language. We will then describe the architecture of the system and the choices made for its portability to the Web. Then, we will present the extensions specific to the Javascript version and in particular the support of signal processing objects. Finally, we will show how INScore's communication system has been extended to allow online musical score control from a native version of INScore, paving the way for real-time performance on the web.