[allertonm]

If you are coding for the browser, neither of the options you suggest are available to you. Now what?

Answer: you do it with callbacks, because they are literally the only mechanism available. Welcome (back) to callback hell.

[jblow]

Hence my caveat about not being able to avoid it if an API forces you to use them.

But if I were making a replacement language that runs in the browser, among the highest priorities would be to make it not work via callbacks.