Bug in page:WebIDL Binder

The page does not tell you

- how to run webidl_binder.py. Since emsdk does not put the containing directory in $PATH when installing, it would seem you aren't supposed to run it by just typing the command. Is there some emcc magic you are supposed to use?
- if you can or cannot use WebIDL to bind to c code
- how to return a Javascript object from the C/C++ side
- Related to the above, how to look in the module properties, i.e., do something like
```
// Find the WebGLTexture for texture.
val texture = val::module_property("GL")["textures"][texname];
```
- how C++ will receive something like an ArrayBuffer from the JS side
- how enumeration names from the IDL get mapped to enumeration values on the JS side.

URL: ../../../docs/porting/connecting_cpp_and_javascript/WebIDL-Binder