Basic Javascript function Syntax.

gistfile1.js

// A simple function

var greet = function(person, greeting) {
    var text = greeting + ', ' + person;
    console.log(text);
};
greet('Iwan', 'Hello');

// A Function that returns a value

var greet = function(person, greeting) {
    var text = greeting + ', ' + person;
    return text;
};

console.log(greet('Iwan','hello'));

// A Function that returns another function

var greet = function(person, greeting) {
    var text = greeting + ', ' + person;
    return function() { console.log(text); };
};

var greeting = greet('Iwan', 'Hello');
greeting();