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JavaScript Objects HTML DOM ObjectsJavaScript Number Object
JavaScript has only one type of number.
Numbers can be written with, or without decimals.
JavaScript Numbers
JavaScript numbers can be written with, or without decimals:
Example
var
pi=3.14; // Written with decimals
var x=34; // Written without decimals
var x=34; // Written without decimals
Extra large or extra small numbers can be written with scientific (exponent) notation:
Example
var y=123e5; // 12300000
var z=123e-5; // 0.00123
var z=123e-5; // 0.00123
All JavaScript Numbers are 64-bit
JavaScript is not a typed language. Unlike many other programming languages, it does not define different types of numbers, like integers, short, long, floating-point etc.
All numbers in JavaScript are stored as 64-bit (8-bytes) base 10, floating point numbers.
Precision
Integers (numbers without a period or exponent notation) are considered accurate up to 15 digits.
The maximum number of decimals is 17, but floating point arithmetic is not always 100% accurate:
Octal and Hexadecimal
JavaScript interprets numeric constants as octal if they are preceded by a
zero, and as hexadecimal if they are preceded by a zero and x.
Example
var y=0377;
var z=0xFF;
var z=0xFF;
 |
Never write a number with a leading zero, unless you want an octal conversion. |
|---|
Number Properties and Methods
Properties:
- MAX VALUE
- MIN VALUE
- NEGATIVE INFINITY
- POSITIVE INFINITY
- NaN
- prototype
- constructor
Methods:
- toExponential()
- toFixed()
- toPrecision()
- toString()
- valueOf()
Complete Number Object Reference
For a complete reference of all the properties and methods that can be used with the Number object, go to our Complete Number Object Reference.
The reference contains both descriptions and examples, for each property and method.
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