This example tries to explain the function scope of javacript.

javascript-scope.js

/*jslint node: true, maxlen: 80, indent: 4 */
"use strict";

var paco = "paco";

function fun1(paco) {
    console.log(paco);
}

function fun2() {
    var paco = "francisco";

    return function fun3() {
        console.log(paco);
    };
}

console.log(paco);
fun1("kiko");
fun2()();