[Chapter 21] Reference: Math
Author: David Flanagan
Date: Fri Aug 29 11:17:34 1997

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| Chapter 21 JavaScript Reference |

# Math Object

## Name

Math Object---placeholder for mathematical functions and constants

## Availability

Navigator 2.0, Internet Explorer 3.0

## Synopsis

    Math.constant
    Math.function()

## Constants

`E`

  the constant e, the base of the natural logarithm.

`LN10`

  the natural logarithm of 10

`LN2`

  the natural logarithm of 2

`LOG10E`

  the base-10 logarithm of e

`LOG2E`

  the base-2 logarithm of e

`PI`

  the constant pi

`SQRT1_2`

  1 divided by the square root of 2

`SQRT2`

  the square root of 2

## Functions

`abs()`

  compute an absolute value

`acos()`

  compute an arc cosine

`asin()`

  compute an arc sine

`atan()`

  compute an arc tangent

`atan2()`

  compute the angle from the X axis to a point

`ceil()`

  round a number up

`cos()`

  compute a cosine

`exp()`

  compute an exponent of e

`floor()`

  round a number down

`log()`

  compute a natural logarithm

`max()`

  return the larger of two numbers

`min()`

  return the smaller of two numbers

`pow()`

  compute xy

`random()`

  compute a random number; not available on all platforms

`round()`

  round to the nearest integer

`sin()`

  compute a sine

`sqrt()`

  compute a square root

`tan()`

  compute a tangent

## Description

`Math` is a read-only reference to a placeholder object that contains mathematical functions and constants. These functions and constants are conveniently grouped by this `Math` object, and are invoked with syntax like this:

    y = Math.sin(x);
    area = radius * radius * Math.PI;

`Math` is actually a "global" property of the Window object, and as such, is usually referred to as `Math`, rather than as `window``.Math`.

`Math` is not a class of objects like Date and String are. The Date class, for example, defines methods that operate on Date objects; on instances of the class. `Math`, on the other hand is simply an object that contains references to functions. These functions happen to be invoked through the `Math` object, but they do not operate on that object, as methods would.

## See Also

"Number"

Location.search |  | Math.abs()