JavaScript- Strings

A String is a set of characters.

It can contain any text data.

It should be surrounded with either Single Quote (') or Double quote (").
[Note: Be consistent]

• 'A Text Data'
• "A Text Data"
• ""

Assigning string to a variable

var name = "John Doe";

Some special charcters can be represented with Escape sequence

Following are the commonly used Escape sequence

• \n- New Line
• \r- Carriage Return
• \t- Tab
• \t- Tab

var message = "Hi\r\nGood Morning";

Concatenation

Multiple Strings can be combined to form one string.
Plus (+) operator can be used.

var message = "Hi" +
"\r\nGood Morning";

JavaScript- Relational Operators- Boolean

Following code fragement will be help you understand the relational operators resulting in boolean values.

var a = 10;
console.log(a == 0); // false
console.log(a == 10); // true

console.log(a != 10); // false
console.log(a != 5); // true

console.log(a > 5); // true
console.log(a > 10); // false
console.log(a > 15); // false
console.log(a >= 10); // true

console.log(a < 5); // false
console.log(a < 10); // false
console.log(a < 15); // true
console.log(a <= 10); // true


JavaScript- Boolean

Boolean variables/expressions refers to one of two values

• true
• false

Boolean expressions are usually generated using relational operators

JavaScript- Basic Arithmetic Operators

Following table shows practical examples to understand how basic arithmetic operator works.

Before		Statement	After	Remarks
x	y		x
Assignment
10	3	x = y	3
Add/Substract/Multiply/Divide
10	3	x = x + y	13	Addition
10	3	x = x - y	7	Subtraction
10	3	x = x * y	30	Multiplication
10	3	x = x / y	3.3333333333333335	Division
10	3	x = x ** y	1000	Power (103)
10	3	x = x % y	1	Reminder of the Division
Shorthand Add/Substract/Multiply/Divide
10	3	x += y	13	Shorthand Addition
10	3	x -= y	7	Shorthand Subtraction
10	3	x *= y	30	Shorthand Multiplication
10	3	x /= y	3.3333333333333335	Shorthand Division
10	3	x **= y	1000	Shorthand Power (103)
10	3	x %= y	1	Reminder of the Division

JavaScript- Understanding Numbers

Below table will help you to understand the values representable with number data type

Statement	i	typeof(i)	Remarks
i = 0	0	number	Fixed point number
i = 1.0	1	number	Floating point number with Zero
i = 1.2	1.2	number	Floating point number
i = 1.2e3	1200	number	Scientific Notation
i = 1.2e200	1.2e+200	number	Scientific Notation
i = 1 / 0	Infinity	number	Divide by Zero
i = NaN	NaN	number	Not a Number
i = 1234567890123456	1234567890123456	number	Precise with 15 digit
i = 12345678901234567	12345678901234568	number	Precision is lost
i = 1.2e20000	Infinity	number	Value cannot be represented with number
i = Number.MIN_VALUE	5e-324	number	Minimum Value for supported by number data type
i = Number.MAX_VALUE	1.7976931348623157e+308	number	Maximum Value for supported by number data type

JavaScript- Data Types

• Number
• All Negative, Positive, Integral and Floating point numbers.
• String
• Characters and Numbers
• Boolean
• True or False
• Object
• Objects, DateTime, Arrays and null etc
• Undefined
• When nothing assigned to a variable
• Or can be assigned to a variable when the existing data is not needed
• Function
• A code block consisting multiple statement to perform a specific purpose 

JavaScript- Getting Started

 To start learning JavaScript, you have to choose a tool through which you can test your "Code" 

There are variety of options available.

Most common one is

• Writing a html page, embed JavaScript and Open it in a browser (ie. Chrome, Edge, Firefox etc).

Few other options are.

•  Install NodeJs and use NodeJS Command line
• Open the browser, open developer tools and use Console to test your JavaScript statements.