Kodegems
Kodegems is a place where you will find a number of tutorials regarding HTML - CSS - WordPress.
What is Javascript
Javascript in a technical way
technical definition from Wikipedia:
JavaScript is a high level dynamic, untyped and interpreted programming language standardized in the ECMAScript language specification, that alongside HTML and CSS is one of the three core technologies of world wide web content.
Javascript in a Practical way
Website consist of 3 layerd architecture
01- HTML
02- CSS
03- Javascript
Tools to Work
01- Code Editor
02- Browser with developer tool
Introduction to Browser Console
Javascript into HTML
Javascript Loading Methods
01- Right away loading
02- Asynchronous loading
03- Deffered Loading
How to write a good javascript
Rule#1
01- Case sensitive
02- Asynchronous loading
03- Deffered Loading
How to write a good javascript
Rule#1
01- Case sensitive
var mehranBlue = "This car is blue";
console.log(mehranblue);
How to write a good javascript
Rule#2
Use camelCase
//variable starts with lowercase letter
var mehranBlue;
//Objects and Classes Start with uppercase letters
var date = Date();
//Constants are all caps
const = CONSTANT;
How to write a good javascript
Rule#3
Whitespace
//With whitespace (human readable)
var dateToday = new Date();
//With no whitespace (machine readable)
var dateToday=new Date();
How to write a good javascript
Rule#4
End each statement with semicolon;
//With Semicolon
var dateToday;
dateToday = new Date();
//With no semicolon
var dateToday
dateToday=new Date()
How to write a good javascript
Rule#5
Use Comments
//With Semicolon
var dateToday = new Date();
/*With no semicolon*/
var dateToday=new Date()
Variables in javascript
Simple mathematics
4 + 5 = 9
Example : Variables
// remember case sensitive
var a;
var A;
var currentTime;
var unit_4;
var $container;
Note: You can not create a variable with number
Example : Variables
// Practical example
var a = 4;
var b = 5;
sum = a+b;
console.log (sum);
Note: You can not create a variable with number
Syntax Example : Variables
// These three are the same
//01
var a = 4;
var b = 5;
var sum = a+b;
//02
var a,b,sum;
a = 5;
b = 4;
sum = a+b;
//03
var a = 5; var b=4; var sum = a+b;Note: You can not create a variable with number
DataTypes in Javascript
- Numeric
- String
- Boolean
- Null
- Undefined
- Symbol
DataTypes in Javascript : Numeric
//Stores regular numbers and integers
var num = 1;
ver integer = 0.32659;
var negNumber = -1;
var negInteger = -3.25689DataTypes in Javascript : String
//Stores strings of letters and symbols
var string = 'Strings are words and sentences';
//Always remember to start with a single quote
var escQuotes = "Quotes can also be \"escaped\".";DataTypes in Javascript : Boolean
//Stores one or other of the binary pair true/false
var theSunIsWarm = true;
var theMoonIsMadeOfCheese = false;DataTypes in Javascript : Null
//Stores the intentional absence of the value
//variable will be empty but not undefined
var emptyInside = null;DataTypes in Javascript : Undefinded
//Placeholder when a variable is not set
var emptyInside;Operators : "="
//basically it looks like something is equal to something
//but in javascript "=" means, you are assigning value to the variable
var a = 5;Short hand Operators : "+=, -=, *=, /= "
//Short hand
var a = 5;
a = a + 5;
//or
a +=5;Unary Operators : ++,--
//Shorthand
var a = 5;
a = a + 1;
//or
a++;
JavaScript Essentials
By Kodegems
