Yes, actions reference other actions in the way you described. If your browser or js object execute js action is trying to talk to a function embedded in an iframe then you have to qualify the iframe to get into it.
For my project, I'm using the ajax object to get the contents of an html file in my files and then running it as html in the iframe object. In this way I'm getting an ESRI map to show up in Construct3 using ESRI's javascript api, and I can access it by calling JS functions in that frame.
However it looks like iFrame is not supported in Construct 3 export to Android so I'd like to do it with something else that is.