Continued from Understanding Variables:
- Boolean – a data type with only two possible values: true or false
- Null – a special data value that has no value and means nothing; not the same as zero
- Number – any series of numeric values, including integers and floating point numbers; can be expressed in decimal ( base 10 ), hexadecimal ( base 16 ), or octal ( base 8 )
- Object – built-in or user-defined classes of data; a collection of properties or attributes
- String – a series of alphanumeric characters, numbers, and punctuation marks
- Undefined – a special data value representing an absence of data; default value for variables declared without a value
When using integers in the Number data type, a leading 0 ( zero ) is used to specify that the integer is octal, and a leading 0x or 0X is used to specify hexadecimal. A floating point number can contain a either a decimal or an “e” to represent “ten to the power of” in scientific notation, or both.