JavaScript Math Object

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The JavaScript Math object provides a collection of mathematical constants and methods for performing such tasks as generating random numbers, rounding, obtaining values such as PI and performing calculations.

JavaScript Math Object Methods

The following table lists the methods available with the Math object:

Method	Description
abs	Absolute value
sin, cos, tan	Standard trigonometric functions; argument in radians
acos, asin, atan, atan2	Inverse trigonometric functions; return values in radians
exp, log	Exponential and natural logarithm, base _e
ceil	Returns least integer greater than or equal to argument
floor	Returns greatest integer less than or equal to argument
min, max	Returns greater or lesser (respectively) of two arguments
pow	Exponential; first argument is base, second is exponent
random	Returns a random number between 0 and 1.
round	Rounds argument to nearest integer
sqrt	Square root

JavaScript Math Object Properties

In addition the math object contains a number of properties for accessing mathematical constants:

Property	Description
E	Euler's constant
LN2	Natural log of 2
LN10	Natural log of 10
LOG2E	Log base -2 of E
LOG10E	Log base -10 of E
PI	Value of Pi
SQRT1_2	Square root of 0.5
SQRT2	Square root of 2

Using JavaScript Math Object and Properties

The first thing to be aware of with the Math object is that an instance of the object already exists. It is not necessary, therefore, to create a new instance using the new keyword. You can simply access the methods and properties by referencing Math.

The methods and properties of the JavaScript Math object can be accessed just as with any other objects (see JavaScript Object Basics for more information). For example we can obtain the value of Pi:

Math.Pi;

We can perform square root calculation:

Math.sqrt(3);

Rounding and Truncating Numbers with the the Math Object

The ceil(), floor() and round() methods of the JavaScript Math object can be used to round numbers up and down:

Math.ceil() - Rounds a number up to the nearest integer

Math.floor() - Rounds a number down to the nearest integer

Math.round() - Rounds a number to the nearest integer (i.e up or down depending on which is closest)

Each of the above methods takes a number as an argument and returns the modified value:


var rounded = Math.round(8.87);