Number

Summary

Creates a wrapper object to allow you to work with numerical values.

Syntax

new Number(value)

Parameters

value

The numeric value of the object being created.

Description

The primary uses for the Number object are:

If the argument cannot be converted into a number, it returns NaN.

In a non-constructor context (i.e., without the new operator), Number can be used to perform a type conversion.

Properties

For properties available on Number instances, see Properties of Number instances.

The largest positive representable number.  The largest negative representable number is -MAX_VALUE.

MAX_VALUE

The smallest positive representable number -- that is, the positive number closest to zero (without actually being zero).  The smallest negative representable number is -MIN_VALUE.

MIN_VALUE

NaN

Special "not a number" value.

NEGATIVE_INFINITY

Special value representing negative infinity; returned on overflow.

POSITIVE_INFINITY

Special value representing infinity; returned on overflow.

prototype

Allows the addition of properties to a Number object.

Methods

For methods available on Number instances, see Methods of Number instances.

isNaN

New in Firefox 15
Determine whether the passed value is NaN.

 

Number instances

All Number instances inherit from Number.prototype. The prototype object of the Number constructor can be modified to affect all Number instances.

Properties

constructor

Returns the function that created this object's instance. By default this is the Number object.

Methods

constructor

Returns the function that created this object's instance. By default this is the Number object.

Examples

Example: Using the Number object to assign values to numeric variables

The following example uses the Number object's properties to assign values to several numeric variables:

var biggestNum = Number.MAX_VALUE;
var smallestNum = Number.MIN_VALUE;
var infiniteNum = Number.POSITIVE_INFINITY;
var negInfiniteNum = Number.NEGATIVE_INFINITY;
var notANum = Number.NaN;

Example: Using Number to convert a Date object

The following example converts the Date object to a numerical value using Number as a function:

var d = new Date("December 17, 1995 03:24:00");
print(Number(d));

This displays "819199440000".

Browser compatibility

See also

• NaN
• The Math global object