Merge pull request #19162 from alalek:backport_18985

diff --cc doc/js_tutorials/js_setup/js_setup/js_setup.markdown
index 89e7acd,55fd40f..1a9ac76
--- 1/doc/js_tutorials/js_setup/js_setup/js_setup.markdown
--- 2/doc/js_tutorials/js_setup/js_setup/js_setup.markdown
+++ b/doc/js_tutorials/js_setup/js_setup/js_setup.markdown
@@@ -128,9 -124,16 +128,16 @@@ Building OpenCV.js from Sourc
  
      For example:
      @code{.bash}
 -    python ./platforms/js/build_js.py build_js --build_test
 +    emcmake python ./opencv/platforms/js/build_js.py build_js --build_test
      @endcode
  
+ -#  [optional] To enable OpenCV contrib modules append `--cmake_option="-DOPENCV_EXTRA_MODULES_PATH=/path/to/opencv_contrib/modules/"`
+ 
+     For example:
+     @code{.bash}
+     python ./platforms/js/build_js.py build_js --cmake_option="-DOPENCV_EXTRA_MODULES_PATH=opencv_contrib/modules"
+     @endcode
+ 
  Running OpenCV.js Tests
  ---------------------------------------
  

diff --cc modules/js/generator/embindgen.py
Simple merge