JavaScript Quick and Dirty Tutorial-Part - 3 ,(Working with Variables and Data Types in JavaScript)

Hey There Guys. Welcome to the third post of this series "Quick and Dirty Introduction to JavaScript". Today we will encounter variables in JavaScript. Please not that variables are very important part of any programming language , because programming is like playing with data and to play with data we must store it somewhere. and we store data in variables.try to remember your high schools math's book there ere variables and constants. Yes variables in JavaScript is same like that. we were using variables in algebra like , a=5,b=10,b=a+b etc. but in JavaSCript we can take variables as full names like

var first_number = 10;
var second_number = 15;
var third_number = first_number + second_number;
alert(third_number);

Creating a Variable in JavaScript is a three way Process.

1. Declaring a variable
2. Giving it a unique name
3. Assign a value to your variable 

like lets take an example you want to create a new variable, for that you would type

var dev = 17;

Here var is a Keyword (don't be confused we will cover the keywords in JavaScript later ) which tells the JavaScript interpreter that dev is a unique name and 17 is it's value.

Rules you must follow while working with variables in JS

Well there are few rules in JS which you must follow like

1. JavaScript is Case Sensitive
Yes Folks JS is Case Sensitive that means ved,Ved and VED all three are different from each other

2. You must begin with a letter,$ or _
That means Ved, My_Num, $My_pay, _NewYork are correct but 1india,%bills,*Jesus are not

3. Your variable name must contain number,$,letters and _
You can’t use spaces or any other special characters anywhere in the variable name: fish&chips and fish and chips aren't legal, but fish_n_chipsand plan9are.

Assigning Variables

To assign a variable you must declare a variable then give it a unique name and in last give it a value like

 var my_age = 22;

Here Var is keyword , my_age is the unique name and 22 is the value of variable my_age

Working with Variables and Data Types in JavaScript

As i told you before that programming is more like playing with data, we play with data and we get new data ummmm like we take three variables a,b and c.we assign values to a  and  b like a = 5, b = 10 anc c = a+b. see what goes on here that we manipulate the data to get new data

 var a = 5;
 var b = 10;
 var c = a+b;

To manipulate we use operators like in c = a+b, + is the operator. In JavaScript there are different operators for different data types

Basic Mathematics with JavaScript

JavaScript Supports Basic Mathematical operations (see the table below)

Lets take an example of Basic Math in JavaScript

    var priceOfOne = 15;
    var totalItem = 5;
    var totalCost = priceOfOne * totalItem;
    alert (totalCost);

In Next Post i will Post some Simple JavaSCript Programs so that you can do exercise. Thanks for reading, see you in next Post :)