Javascript Variables

Hi, Let's Learn Variables in Javascript.

Variable[Variables = Data Containers]

• A JavaScript variable is a named container used to store, reference, and manipulate data values in a program. Because JavaScript is dynamically typed, you do not need to specify the type of data (like text or numbers) when creating a variable; the engine determines it automatically at runtime.




• Variables are identified with unique names called identifiers.

Ex : a=10 ---> a- variable , 10- value

Dynamically Typed vs Statically Typed Languages

Statically Typed Languages

• How it works: Variable data types are known and enforced before the program runs (at compile time).


• Key traits: You must declare types explicitly, and errors are caught early.


• Pros: More optimized, faster execution, fewer surprises in production.


• Examples: C, C++, Java, Rust, Go.

Dynamically Typed Languages

• How it works: Data types are assigned and checked during execution (at runtime).


• Key traits: You don't need to specify variable types, and values can change types freely.


• Pros: Faster setup, more flexible, and code is often quicker to write.


• Examples: Python, JavaScript, Ruby, PHP.

Ways to Declare Variables Modern JavaScript uses three primary keywords to create variables:

• 
  const: Declares a block-scoped constant value that cannot be reassigned after initialization.


• 
  let: Declares a block-scoped mutable variable that can be reassigned later.



• var: Declares a function-scoped variable. This is an older legacy keyword that is mostly avoided in modern code.




• Variables are labels for data values.




• Variables are containers for storing data.