Variables
A variable is an identifier or a name which is used to refer a value. A variable is written with a combination of letters, numbers and special characters _ (underscore) and $ (dollar) with the first letter being an alphabet.
Ex-
c, fact, b33, total_amount etc.
Rules
• Variable can contain combination of letters, digits, underscores ( _ ), and
dollar signs ( $ ).
• Must begin with a letter A-Z or a-z or underscore or dollar sign
• A variable name cannot start with a number
• Must not contain any space characters
• JavaScript is case-sensitive
• Can‟t use reserved keywords