gil00pita
10/27/2015 - 3:08 PM

Introduction to Javascript

Introduction to Javascript

intro.js
content_copyfile_download
 /**
 * Created by Gil Álvaro on 21/08/15.
 */
//Javascript
(function() {
// Single line of comment

/*
 Multiple lines of comments
 */

//debugging
console.log('xD');

//Alerts
alert('Hello World!');

//Variables
var theVar; // == undefined
//avoid to set global variable

var oneVar = 42, // Assigned 42 to the var
    secondVar = 22; // Assigned 22 to the secondVar (no need to add var)

theVar = 'Name';
theVar = oneVar; //overwriting


//DATA TYPES

/*
 NUMBER -> If is not Octal, Exponential or Haxadecimal get Infinity or NaN (Not a Number) it can be cheched with isNan()

 STRING -> Sequence of characters within single or double quotes, can nest quotes inside quotes but must match

 To joind strings we use + sign like 'wait, ' + 'for'

 BOOLEAN

 Falsey values
 -false
 -0
 -''
 -null
 -undefined
 -NaN
 Truely values
 All others

 UNDEFINED

 NULL

 */

//ARRAYS

var myArray = [5,'something',true];

//access array
console.log( myArray[0] );


// OBEJCTS ARRAYS

var myObject = {
    myNumber: 10,
    myString: 'Woooho!'
};
var string = 'hello';
var stringObject = new String('An object string');

//access Object Array
console.log(myObject.myNumber); //10
console.log(myObject['myString']); //'Woooho!'
// incrementing
secondVar += 1;
//decrementing
secondVar -= 1;
//multiplication
secondVar *= 2;
//division
secondVar /= 2;
//Rest
secondVar %= 1;


//Comparison -> avoid non strict comparisons
1 == true; //non strict comparison = true
1 === true; //sctrict comparison = false

//Unary Operators

+true;
-true;
typeof true;

//Logical Operators
(1 && 2);
(true || false);

//Operator precedence

3 + 4 * 5; //returns 23

// FUNCTTIONS
function myFunction(){
	console.log("This is a Function!!");
}

function getThingByColour(colour) {
    var things = {
        red: 'a red thing',
        green: 'a green thing',
        blue: 'a blue thing'
    };

    return things[colour] || 'Sorry, no thing of that colour exists';
}
//Run automaticly when the code is loaded
(function invokeImmediately() {
    console.log('invoked automatically');
}());

!function alsoInvokedAutomatically() {
    console.log('invoked automatically too');
}();

//SCOPE

//Global Vars
var global = 1;
function aFunction() {
    var local = 2;
    console.log(global);
    console.log(local);
    console.log(window.location.href);
}

//This
//usually an Object


//Strict Mode affect this

(function () {
    'use strict';
    console.log(this);

    var object = {
        property: 'I belong to this',
        method: function () {
            return this.property;
        }
    }

    console.log(object.method());

    function Person(name) {
        this.name = name;
    }

    var bob = new Person('Bob');
    console.log(bob.name);
}());

})();
intro.html
content_copyfile_download
<!DOCTYPE html>
<html>
<script src="intro.js" ></script>
<head lang="en">
    <meta charset="UTF-8">
    <title></title>
</head>
<body>

</body>
</html>