6 - Javascript:Objects - The math object
The built-in Math object includes mathematical constants and functions. You do not need to create the Math object before using it.
For instance, to store a random number between 0 and 1 in a variable called "r_number":
r_number=Math.random()
To store the rounded number of 8.6 in a variable called "r_number":
r_number=Math.round(8.6)
The Math object's properties and methods are described below:
NN: Netscape, IE: Internet Explorer
Properties
Syntax: object.property_name
| Property | Description | NN | IE |
|---|---|---|---|
| E | Returns the base of a natural logarithm | 2 | 3 |
| LN2 | Returns the natural logarithm of 2 | 2 | 3 |
| LN10 | Returns the natural logarithm of 10 | 2 | 3 |
| LOG2E | Returns the base-2 logarithm of E | 2 | 3 |
| LOG10E | Returns the base-10 logarithm of E | 2 | 3 |
| PI | Returns PI | 2 | 3 |
| SQRT1_2 | Returns 1 divided by the square root of 2 | 2 | 3 |
| SQRT2 | Returns the square root of 2 | 2 | 3 |
Methods
Syntax: object.method_name()
| Method | Description | NN | IE |
|---|---|---|---|
| abs(x) | Returns the absolute value of x | 2 | 3 |
| acos(x) | Returns the arccosine of x | 2 | 3 |
| asin(x) | Returns the arcsine of x | 2 | 3 |
| atan(x) | Returns the arctangent of x | 2 | 3 |
| atan2(y,x) | Returns the angle from the x axis to a point | 2 | 3 |
| ceil(x) | Returns the nearest integer greater than or equal to x | 2 | 3 |
| cos(x) | Returns the cosine of x | 2 | 3 |
| exp(x) | Returns the value of E raised to the power of x | 2 | 3 |
| floor(x) | Returns the nearest integer less than or equal to x | 2 | 3 |
| log(x) | Returns the natural log of x | 2 | 3 |
| max(x,y) | Returns the number with the highest value of x and y | 2 | 3 |
| min(x,y) | Returns the number with the lowest value of x and y | 2 | 3 |
| pow(x,y) | Returns the value of the number x raised to the power of y | 2 | 3 |
| random() | Returns a random number between 0 and 1 | 2 | 3 |
| round(x) | Rounds x to the nearest integer | 2 | 3 |
| sin(x) | Returns the sine of x | 2 | 3 |
| sqrt(x) | Returns the square root of x | 2 | 3 |
| tan(x) | Returns the tangent of x | 2 | 3 |
(from w3schools.com)