What's the purpose of using Function.call.apply in JavaScript?

Question

I was browsing through the JavaScript Garden when I stumbled upon the Function.call.apply hack which is used to create \"fast, unbound wrappers\". It says:

Answer 1

It means you can use the methods from an object on another one.

A good example is the arguments variable all functions have, it's like an array but not an array so you can call array's methods on it thus:

Array.prototype.join.call(arguments, ",");