Variables in JavaScript

A variable serves as a placeholder for storing data in JavaScript. To declare a variable, you use the var keyword followed by the variable name, which is also known as an identifier.

Syntax:

var variable_name;

The var command is utilized for variable declaration.

Examples:

var name;
var empno;
var name, empno, address;

Rules for Variables:

• Variables cannot be reserved words or keywords used by JavaScript.
• Variable names must start with a letter or an underscore (_) and cannot begin with symbols, numbers, or mathematical notations.
• Variable names cannot contain spaces.

Notes:

While JavaScript allows variables to be used without prior declaration, it's considered good programming practice to initialize all variables.

Variable names in JavaScript are case-sensitive, meaning X is distinct from x.

Understanding these rules and practices is crucial for effectively using variables in JavaScript programming.