message: js docker build docs emcc latest warning
diff: @@ -117,14 +117,41 @@ So, make sure [docker](https://www.docker.com/) is installed in your system and
  @code{.bash}
  git clone https://github.com/opencv/opencv.git
  cd opencv
  -docker run --rm --workdir /code -v "$PWD":/code "trzeci/emscripten:latest" python ./platforms/js/build_js.py build_js
  +docker run --rm --workdir /code -v "$PWD":/code "trzeci/emscripten:latest" python ./platforms/js/build_js.py build
  @endcode
  In Windows use the following PowerShell command:
  @code{.bash}
  -docker run --rm --workdir /code -v "$(get-location):/code" "trzeci/emscripten:latest" python ./platforms/js/build_js.py build_js
  +docker run --rm --workdir /code -v "$(get-location):/code" "trzeci/emscripten:latest" python ./platforms/js/build_js.py build
  @endcode
  -@note
  -The example uses latest version of [trzeci/emscripten](https://hub.docker.com/r/trzeci/emscripten) docker container. At this time, the latest version works fine and is `trzeci/emscripten:sdk-tag-1.38.32-64bit`
  +@warning
  +The example uses latest version of emscripten. If the build fails you should try a version that is known to work fine which is `1.38.32` using the following command:
  +
  +@code{.bash}
  +docker run --rm --workdir /code -v "$PWD":/code "trzeci/emscripten:sdk-tag-1.38.32-64bit" python ./platforms/js/build_js.py build
  +@endcode
  +
  +### Building the documentation with Docker
  +
  +To build the documentation `doxygen` needs to be installed. Create a file named `Dockerfile` with the following content:
  +
  +```
  +FROM trzeci/emscripten:sdk-tag-1.38.32-64bit
  +
  +RUN apt-get update -y
  +RUN apt-get install -y doxygen
  +```
  +
  +Then we build the docker image and name it `opencv-js-doc` with the following command (that needs to be run only once):
  +
  +@code{.bash}
  +docker build . -t opencv-js-doc
  +@endcode
  +
  +Now run the build command again, this time using the new image and passing `--build_doc`:
  +
  +@code{.bash}
  +docker run --rm --workdir /code -v "$PWD":/code "opencv-js-doc" python ./platforms/js/build_js.py build --build_doc
  +@endcode
  