When combining two or more JavaScript modules together, the first thing to consider is the use of CF.userMain function.
This function can only be implemented once in your entire project - see here for more details on this.

As an example, lets say we have two scripts in our project, but both have defined their own CF.userMain() function, like so:

Script1.js

CF.userMain = function() {
    // iViewer initialization is now complete and the CF environment is fully available

    // Watch for page flips
    CF.watch(CF.PageFlipEvent, onPageFlip);

    // Watch for network status, get initial status
    CF.watch(CF.NetworkStatusChangeEvent, onNetworkStatusChange);

    // Watch for important system connects and disconnects
    CF.watch(CF.ConnectionStatusChangeEvent, "TEST-SYSTEM", onTestSystemConnectionStatusChange, true);
    CF.watch(CF.ConnectionStatusChangeEvent, "SERVER SYSTEM", onServerSystemConnectionStatusChange, true);

    // Watch for some crucial join changes
    CF.watch(CF.JoinChangeEvent, ["d10", "d11", "d12", "a50"], onImportantJoinChange);
};

Script2.js

CF.userMain = function() {
	// Create interlock group for buttons
Interlock.create("buttons", "d1","d2","d3","d4");

	// Create an interlock group for subpages
	Interlock.create("subpages", ["d100", "d200", "d300", "d400"]);

	// Setup a watch callback to display the current selection
	Interlock.watch("buttons", function(group, currentSelection, previousSelection) {
		CF.setJoin("s1", "Current selection in group 1 is " + currentSelection);
		// show the subpage associated with interlock group 1
		// do it the lazy way - d1 becomes d100, d2 becomes d200 etc
		// when we show one of the subpages, the subpages interlock group kicks in and hides the others
		Interlock.select("subpages", currentSelection+"00");
	});

	// Set the group initial values
	Interlock.select("buttons", "d2");
};