Examples: You can look into the standard Liferay fragments, the basic components Slider or Tabs contain Javascript.
The Javascript code in the Javascript window is encapsulated inside of a function and therefore hidden. That's actually good, very good because the stuff in there would otherwise pollute the global namespace.
There are numerous tutorials out there explaining that practice, e.g.
https://www.tutorialspoint.com/javascript-encapsulation-using-anonymous-functionsThere are two ways around this, one as Liferay does it, attaching events to objects/buttons and so on in that unnamed function. The other way, that also makes sense in some usecases, is to add your functions to the window object.
window.foo = function() { ... }
I would advise to use the first way, if possible.
