yeukhon/foo.js

## foo.js
var Foo = function () {
    alert("Hello! You've just called Foo()");
}

module.exports = Foo

## index.html
<html>
<body>

<script src="bundle.js"></script>
</body>

</html>

## index.js
var Foo = require("./foo.js")
	var Foo = function () {
	alert("Hello! You've just called Foo()");
	}

	module.exports = Foo