You might ask Why in Javascript?

Guys just imagine that you have a long mass of coded project in C/C++ and you all want it in Java Script ,so asto port it to the web .

You might ask Why in Javascript?

well because although you can do it by many high level languages but you need many plugins and it dosen’t work always as expected.
Java script are currently supported analmost all browsers.
Emscripten
is an LLVM to JavaScript compiler using which you can combine C and C++ code into java script. It takes LLVM bitcode (which can be generated from C/C++ using Clang, or any other language that can be converted into LLVM bitcode) and compiles that into JavaScript, which can be run on the web (or anywhere else JavaScript can run).
Using Emscripten, you can
Compile C and C++ code into JavaScript