main knowledge of JavaScript

1. Variables
2. Operators
3. Datatypes
4. Conditional
5. Loops
6. Function
7. Objects
8. Class

Definition

variable :it is a container store any type of data.
Datatype : Any data which type you have store
conditional : you have any work different types
loop : it's iterations work finite or infinity time.
Function : it's block of code which task perform many time under control of user.
Object : This is collection of key and value.
Class : The class is rarely use . it is collection of object and methods