Number- consist of integer and floating- point number and the special NaN value. Numbers use a 64-bit IEEE 754 format. Boolean-consist of logical value, true and false. String- consists of string values that are enclosed in single or double quotes. The nu11type- consists of single value, nu11, which identify a null, empty or nonexistent reference.
It is possible for a variable to be assigned a value of one type and then later in the script’s execution be assigned a value of another type. For example, the variable total could be assigned 123, then the sum of all accounts, and then true. The type of the variable would change with the type of the value assigned to it. The different types of literal values that can be assigned to a variable are covered in the following subsections.