  We describe jsCcoq, a new platform and user environment for the Coq
interactive proof assistant. The jsCoq system targets the HTML5-ECMAScript 2015
specification, and it is typically run inside a standards-compliant browser,
without the need of external servers or services. Targeting educational use,
jsCoq allows the user to start interaction with proof scripts right away,
thanks to its self-contained nature. Indeed, a full Coq environment is packed
along the proof scripts, easing distribution and installation. Starting to use
jsCoq is as easy as clicking on a link. The current release ships more than 10
popular Coq libraries, and supports popular books such as Software Foundations
or Certified Programming with Dependent Types. The new target platform has
opened up new interaction and display possibilities. It has also fostered the
development of some new Coq-related technology. In particular, we have
implemented a new serialization-based protocol for interaction with the proof
assistant, as well as a new package format for library distribution.
