emkay

var people = ['Bob', 'Sally', 'Sara', 'Frank'];

console.log(people.length); // 4

var i;
var len = people.length;
for (i = 0; i < len; i += 1) {
    console.log(people[i]);
}

emkay

var a = 100,
    b = 0;

function change() {
   var b = a + 5;
}

change();

alert(b);

emkay

var person = {
    first_name: "Robert",
    last_name: "Barker",
    nick_name: "Bob",
    full_name: undefined,
    name_helper: function (short) {
        var that = this; // the important part
        var shorter_name = function () {
            // this to that
            that.full_name = that.nick_name + " " + that.last_name;

emkay

var person = {
    first_name: "Robert",
    last_name: "Barker",
    nick_name: "Bob",
    full_name: undefined,
    name_helper: function (short) {
        var shorter_name = function () {
            this.full_name = this.nick_name + " " + this.last_name;
        };
        

emkay

var counter = {
    value: 0,
    increment: function () {
        this.value += 1;
    },
    reset: function () {
        this.value = 0;
    }
};

emkay

// add
var add = function (a, b) {
    return a + b;
};

// or

function add (a, b) {
    return a + b;
}

emkay

var person = {
    "name": "Bob Barker"
};

person.name = "Batman";

//or 

person["name"] = "Batman";

emkay

var student = {
    "name": "Bob Barker",
    "age": 100
};

console.log(student.name);
console.log(student.age);

console.log(student["name"]);

emkay

function sum(x, y) {
    // antipattern: implied global
    result = x + y;
    return result;
}


function sum(x, y) {
    var result = x + y;
    return result;

emkay

document.writeln('hello world!'); // using the document object to directly write to the page

alert('hello world!'); // issuing an alert dialog box.

console.log('hello world!'); // writing to the browser console.