How exactly callbacks get their arguments?

Question

I have trouble understanding how callbacks in JavaScript get their arguments. Or in other words: how to implement a higher-order function so its callback accepts for instance a

Answer 1

Arguments are passed to a function when that function is called.

function foo(arg) {
    console.log(arg);
}

foo("This is the value");

This is still true when it is a callback function.

function foo(arg) {
    console.log(arg);
}

function bar(callback) {
    callback("This is the value");
}

bar(foo);

And it is still true when the callback function is called by code written by someone else that exists in a library you aren't examining the source code of.