How do I access c3runtime variables from external javascript

For the game developed in Construct2, global variables can be accessed using

var runtime = document.getElementById('c2canvas').c2runtime;

in same way how do I access c3runtime variables from external java script

This isn't supported, nor does it seem like a particularly good idea. Why not add an action to a plugin to pass the relevant data? Then that can be a global variable or an expression coming from somewhere else.

If that game is developed by us that works, whereas I want to access in other games also, there are few websites they are doing but not revealing the method