Core JavaScript 1.5 Reference:Global Objects:Number

From MDC

Contents 1 Summary 2 Syntax 3 Parameters 4 Description 5 Properties 6 Methods 7 Number instances 7.1 Properties 7.2 Methods 8 Examples 8.1 Example: Using the Number object to assign values to numeric variables 8.2 Example: Using Number to convert a Date object 9 See also

[edit] Summary

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

[edit] Syntax

new Number(value)

[edit] Parameters

value

The numeric value of the object being created.

[edit] 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.

[edit] Properties

For properties inherited by Number instances, see Properties of Number instances.

MAX_VALUE

The largest representable number.

MIN_VALUE

The smallest representable number.

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.

[edit] Methods

For methods inherited by Number instances, see Methods of Number instances.

Although the Number object contains no methods of its own, it does inherit some methods through the prototype chain.

[edit] Number instances

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

[edit] Properties

constructor

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

[edit] Methods

toExponential

Returns a string representing the number in exponential notation.

toFixed

Returns a string representing the number in fixed-point notation.

toLocaleString

Returns a human readable string representing the number using the locale of the environment. Overrides the Object.prototype.toLocaleString method.

toPrecision

Returns a string representing the number to a specified precision in fixed-point or exponential notation.

toSource

Non-standard

Returns an object literal representing the specified Number object; you can use this value to create a new object. Overrides the Object.prototype.toSource method.

toString

Returns a string representing the specified object. Overrides the Object.prototype.toString method.

valueOf

Returns the primitive value of the specified object. Overrides the Object.prototype.valueOf method.

[edit] Examples

[edit] 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:

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

[edit] 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".

[edit] See also

• NaN