Introduction:-javascript is an object oriented programming language used by several websites for scripting  webpages. It is an interpreated programming language which enables dynamic interactivity on websites.

Features of javascript:-

1.all the websites support javascript, they provide built in execution environment.

2. it is a structured programming, it follows c programming language syntax and structure.

3. it is a case sensitive programming language.

4. it is a light weight interpreated language.

5. it is supportable in several operating system including macOS, windows etc.

Places to put JavaScript code:-

1. Between head tag.
2. Between body tag.
3.  In external file(.js file)

javascriptComment:- it is a meaningful way to deliver messange,warning,suggestion or information about the code .

there are 2 types of javascript comment:

1. Single-line comment
2. Multi-line comment
3. Single line comment:-  single line comment is used by adding forward slashes(//) before the line.
4. Multi line comment:- it is represented by forward slash with asterisk then asterisk with forward slash.

Example:-/* code is here*/

JavaScript variable:- variable in javascript is a name of storage location.

There are 2 types of variables:-

1. Local variable
2. Global variable

Local variable:- Javascript local variable is declared inside the lock or function. It is accessible within the function or block.

Global variable:- It is declared outside the function and accessible from any function.

Javascript datatypes:-Datatypes hold different types of values.

There are two types of data types:-

1. Primitive data type(string,number,Boolean undefined,null)
2. Non-primitive data type(object,Array,RegExp)

Javascript operators:-

. javascript operators are the symbol which are used to perform operations on operands

1.Arithmetic Operators

2. Comparison (relational) operators

3. Bitwise Operators

4. logical Operatiors

5. Assignment Operators

6. Special Operators

Javascript if-else:

If else statement is used to execute wheather condition is true or false.

There are three forms of if ststements in javascript:-

1. If statement
2. If else statement
3. If else if statement