The primitive data types

            Number

            String

            Boolean

Terms to know...

            integer

            floating-point value

            exponent

            empty string

            escape sequence

            Boolean value

 

Rules for creating identifiers in JavaScript

            Identifiers can only contain letters, numbers, the underscore, and the $.

            Identifiers canít start with a number.

            Identifiers are case-sensitive.

            Identifiers can be any length.

            Identifiers canít be the same as reserved words.