"Data Types - Number
In JavaScript, every number data type is treated as a
floating-point number. A floating-point number is a number that
includes a decimal place. For example, the fraction one-half
wouldn't be written as .5, but as 0.5. Multiply that 0.5 by 6.1234
(or any number, really), and the decimal (the "point") will have
"floated" to a new position within the new number. Hence the term
"Floating Point". Because of this floating-point capability,
JavaScript is great to use with numbers. Combine this with its
loosely typed nature and you get a very easy to use and flexible
yet powerful programming language.

"Within the Numbers data type, there are a few different
variations that must be addressed. Understanding these variations
is crucial to your skill in working with them. As with most
concepts within JavaScript, they are easy to understand. Along with
the different number types are several built in number values that
can be used within your scripts. The different types and built in
values are as follows. Integers

"An integer is a number that exists without a decimal place. It
is a whole number. For example, the number 5 would be an integer,
but the number 5.5 would not be due to the existence of a decimal
place. An integer may be positive or negative. An integer may be
stated as a decimal, octal, or hexadecimal number. The below list
explains what is meant by the terms decimal, octal, and
hexadecimal."