The CEF3 document describing JavaScript integration is here :
https://bitbucket.org/chromiumembedded/cef/wiki/JavaScriptIntegration.md
The following button registers myFunc() using a "register" function we previously binded to the window in the GlobalCEFApp.OnContextCreated event.
After registering the function you can right-click over this demo and select "Execute registered JS function" to execute the function.