Math object's PI property has the value of pi.
| Core object. | |
| Implemented in | Navigator 2.0, LiveWire 1.0 |
Created by
The Math object is a top-level, predefined JavaScript object. You can automatically access it without using a constructor or calling a method.
Description
All properties and methods of Math are static. You refer to the constant PI as Math.PI and you call the sine function as Math.sin(x), where x is the method's argument. Constants are defined with the full precision of real numbers in JavaScript.
It is often convenient to use the with statement when a section of code uses several Math constants and methods, so you don't have to type "Math" repeatedly. For example,
with (Math) {
a = PI * r*r
y = r*sin(theta)
x = r*cos(theta)
} Property Summary
Properties
E
Euler's constant and the base of natural logarithms, approximately 2.718.
| Property of |
Math
|
| Static, Read-only | |
| Implemented in | Navigator 2.0, LiveWire 1.0 |
Examples
The following function returns Euler's constant:
function getEuler() {
return Math.E
} Description
Because E is a static property of Math, you always use it as Math.E, rather than as a property of a Math object you created.
LN10
The natural logarithm of 10, approximately 2.302.
| Property of |
Math
|
| Static, Read-only | |
| Implemented in | Navigator 2.0, LiveWire 1.0 |
Examples
The following function returns the natural log of 10:
function getNatLog10() {
return Math.LN10
} Description
Because LN10 is a static property of Math, you always use it as Math.LN10, rather than as a property of a Math object you created.
LN2
The natural logarithm of 2, approximately 0.693.
| Property of |
Math
|
| Static, Read-only | |
| Implemented in | Navigator 2.0, LiveWire 1.0 |
Examples
The following function returns the natural log of 2:
function getNatLog2() {
return Math.LN2
} Description
Because LN2 is a static property of Math, you always use it as Math.LN2, rather than as a property of a Math object you created.
LOG10E
The base 10 logarithm of E (approximately 0.434).
| Property of |
Math
|
| Static, Read-only | |
| Implemented in | Navigator 2.0, LiveWire 1.0 |
Examples
The following function returns the base 10 logarithm of E:
function getLog10e() {
return Math.LOG10E
} Description
Because LOG10E is a static property of Math, you always use it as Math.LOG10E, rather than as a property of a Math object you created.
LOG2E
The base 2 logarithm of E (approximately 1.442).
| Property of |
Math
|
| Static, Read-only | |
| Implemented in | Navigator 2.0, LiveWire 1.0 |
Examples
The following function returns the base 2 logarithm of E:
function getLog2e() {
return Math.LOG2E
} Description
Because LOG2E is a static property of Math, you always use it as Math.LOG2E, rather than as a property of a Math object you created.
PI
The ratio of the circumference of a circle to its diameter, approximately 3.14159.
| Property of |
Math
|
| Static, Read-only | |
| Implemented in | Navigator 2.0, LiveWire 1.0 |
Examples
The following function returns the value of pi:
function getPi() {
return Math.PI
} Description
Because PI is a static property of Math, you always use it as Math.PI, rather than as a property of a Math object you created.
SQRT1_2
The square root of 1/2; equivalently, 1 over the square root of 2, approximately 0.707.
| Property of |
Math
|
| Static, Read-only | |
| Implemented in | Navigator 2.0, LiveWire 1.0 |
Examples
The following function returns 1 over the square root of 2:
function getRoot1_2() {
return Math.SQRT1_2
} Description
Because SQRT1_2 is a static property of Math, you always use it as Math.SQRT1_2, rather than as a property of a Math object you created.
SQRT2
The square root of 2, approximately 1.414.
| Property of |
Math
|
| Static, Read-only | |
| Implemented in | Navigator 2.0, LiveWire 1.0 |
Examples
The following function returns the square root of 2:
function getRoot2() {
return Math.SQRT2
} Description
Because SQRT2 is a static property of Math, you always use it as Math.SQRT2, rather than as a property of a Math object you created.
Methods
abs
Returns the absolute value of a number.
| Method of |
Math
|
| Static | |
| Implemented in | Navigator 2.0, LiveWire 1.0 |
x | A number |
Examples
The following function returns the absolute value of the variable x:
function getAbs(x) {
return Math.abs(x)
} Description
Because abs is a static method of Math, you always use it as Math.abs(), rather than as a method of a Math object you created.
acos
Returns the arccosine (in radians) of a number.
| Method of |
Math
|
| Static | |
| Implemented in | Navigator 2.0, LiveWire 1.0 |
x | A number |
Description
The acos method returns a numeric value between 0 and pi radians. If the value of number is outside this range, it returns 0.
Because acos is a static method of Math, you always use it as Math.acos(), rather than as a method of a Math object you created.
Examples
The following function returns the arccosine of the variable x:
function getAcos(x) {
If you pass -1 to
return Math.acos(x)
}getAcos, it returns 3.141592653589793; if you pass 2, it returns 0 because 2 is out of range.
See also
Math.asin, Math.atan, Math.atan2, Math.cos, Math.sin, Math.tan
asin
Returns the arcsine (in radians) of a number.
| Method of |
Math
|
| Static | |
| Implemented in | Navigator 2.0, LiveWire 1.0 |
x | A number |
Description
The asin method returns a numeric value between -pi/2 and pi/2 radians. If the value of number is outside this range, it returns 0.
Because asin is a static method of Math, you always use it as Math.asin(), rather than as a method of a Math object you created.
Examples
The following function returns the arcsine of the variable x:
function getAsin(x) {
If you pass
return Math.asin(x)
}getAsin the value 1, it returns 1.570796326794897 (pi/2); if you pass it the value 2, it returns 0 because 2 is out of range.
See also
Math.acos, Math.atan, Math.atan2, Math.cos, Math.sin, Math.tan
atan
Returns the arctangent (in radians) of a number.
| Method of |
Math
|
| Static | |
| Implemented in | Navigator 2.0, LiveWire 1.0 |
x | A number |
Description
The atan method returns a numeric value between -pi/2 and pi/2 radians.
Because atan is a static method of Math, you always use it as Math.atan(), rather than as a method of a Math object you created.
Examples
The following function returns the arctangent of the variable x:
function getAtan(x) {
If you pass
return Math.atan(x)
}getAtan the value 1, it returns 0.7853981633974483; if you pass it the value .5, it returns 0.4636476090008061.
See also
Math.acos, Math.asin, Math.atan2, Math.cos, Math.sin, Math.tan
atan2
Returns the arctangent of the quotient of its arguments.
| Method of |
Math
|
| Static | |
| Implemented in | Navigator 2.0, LiveWire 1.0 |
y, x | Number |
Description
The atan2 method returns a numeric value between -pi and pi representing the angle theta of an (x,y) point. This is the counterclockwise angle, measured in radians, between the positive X axis, and the point (x,y). Note that the arguments to this function pass the y-coordinate first and the x-coordinate second.
atan2 is passed separate x and y arguments, and atan is passed the ratio of those two arguments.
Because atan2 is a static method of Math, you always use it as Math.atan2(), rather than as a method of a Math object you created.
Examples
The following function returns the angle of the polar coordinate:
function getAtan2(x,y) {
If you pass
return Math.atan2(x,y)
}getAtan2 the values (90,15), it returns 1.4056476493802699; if you pass it the values (15,90), it returns 0.16514867741462683.
See also
Math.acos, Math.asin, Math.atan, Math.cos, Math.sin, Math.tan
ceil
Returns the smallest integer greater than or equal to a number.
| Method of |
Math
|
| Static | |
| Implemented in | Navigator 2.0, LiveWire 1.0 |
x | A number |
Description
Because ceil is a static method of Math, you always use it as Math.ceil(), rather than as a method of a Math object you created.
Examples
The following function returns the ceil value of the variable x:
function getCeil(x) {
If you pass 45.95 to
return Math.ceil(x)
}getCeil, it returns 46; if you pass -45.95, it returns -45.
See also
Math.floor
cos
Returns the cosine of a number.
| Method of |
Math
|
| Static | |
| Implemented in | Navigator 2.0, LiveWire 1.0 |
x | A number |
Description
The cos method returns a numeric value between -1 and 1, which represents the cosine of the angle.
Because cos is a static method of Math, you always use it as Math.cos(), rather than as a method of a Math object you created.
Examples
x:
function getCos(x) {
return Math.cos(x)
}
If x equals Math.PI/2, getCos returns 6.123031769111886e-017; if x equals Math.PI, getCos returns -1.
Math.acos, Math.asin, Math.atan, Math.atan2, Math.sin, Math.tan
exp
Returns Ex, where x is the argument, and E is Euler's constant, the base of the natural logarithms.
| Method of |
Math
|
| Static | |
| Implemented in | Navigator 2.0, LiveWire 1.0 |
x | A number |
Description
Because exp is a static method of Math, you always use it as Math.exp(), rather than as a method of a Math object you created.
Examples
The following function returns the exponential value of the variable x:
function getExp(x) {
If you pass
return Math.exp(x)
}getExp the value 1, it returns 2.718281828459045.
See also
Math.E, Math.log, Math.pow
floor
Returns the largest integer less than or equal to a number.
| Method of |
Math
|
| Static | |
| Implemented in | Navigator 2.0, LiveWire 1.0 |
x | A number |
Description
Because floor is a static method of Math, you always use it as Math.floor(), rather than as a method of a Math object you created.
Examples
The following function returns the floor value of the variable x:
function getFloor(x) {
If you pass 45.95 to
return Math.floor(x)
}getFloor, it returns 45; if you pass -45.95, it returns -46.
See also
Math.ceil
log
Returns the natural logarithm (base E) of a number.
| Method of |
Math
|
| Static | |
| Implemented in | Navigator 2.0, LiveWire 1.0 |
x | A number |
Description
If the value of number is outside the suggested range, the return value is always -1.797693134862316e+308.
Because log is a static method of Math, you always use it as Math.log(), rather than as a method of a Math object you created.
Examples
The following function returns the natural log of the variable x:
function getLog(x) {
If you pass
return Math.log(x)
}getLog the value 10, it returns 2.302585092994046; if you pass it the value 0, it returns -1.797693134862316e+308 because 0 is out of range.
See also
Math.exp, Math.pow
max
Returns the larger of two numbers.
| Method of |
Math
|
| Static | |
| Implemented in | Navigator 2.0, LiveWire 1.0 |
x, y | Numbers. |
Description
Because max is a static method of Math, you always use it as Math.max(), rather than as a method of a Math object you created.
Examples
The following function evaluates the variables x and y:
function getMax(x,y) {
If you pass
return Math.max(x,y)
}getMax the values 10 and 20, it returns 20; if you pass it the values -10 and -20, it returns -10.
See also
Math.min
min
Returns the smaller of two numbers.
| Method of |
Math
|
| Static | |
| Implemented in | Navigator 2.0, LiveWire 1.0 |
x, y | Numbers. |
Description
Because min is a static method of Math, you always use it as Math.min(), rather than as a method of a Math object you created.
Examples
The following function evaluates the variables x and y:
function getMin(x,y) {
If you pass
return Math.min(x,y)
}getMin the values 10 and 20, it returns 10; if you pass it the values -10 and -20, it returns -20.
See also
Math.max
pow
Returns base to the exponent power, that is, baseexponent.
| Method of |
Math
|
| Static | |
| Implemented in | Navigator 2.0, LiveWire 1.0 |
base | The base number |
exponent |
The exponent to which to raise base
|
Description
Because pow is a static method of Math, you always use it as Math.pow(), rather than as a method of a Math object you created.
Examples
function raisePower(x,y) {
If
return Math.pow(x,y)
}x is 7 and y is 2, raisePower returns 49 (7 to the power of 2).
See also
Math.exp, Math.log
random
Returns a pseudo-random number between 0 and 1. The random number generator is seeded from the current time, as in Java.
| Method of |
Math
|
| Static | |
| Implemented in |
Navigator 2.0, LiveWire 1.0: Unix only Navigator 3.0, LiveWire 1.0: all platforms |
Syntax
random()
Parameters
None.
Description
Because random is a static method of Math, you always use it as Math.random(), rather than as a method of a Math object you created.
Examples
//Returns a random number between 0 and 1
function getRandom() {
return Math.random()
}round
Returns the value of a number rounded to the nearest integer.
| Method of |
Math
|
| Static | |
| Implemented in | Navigator 2.0, LiveWire 1.0 |
x | A number |
Description
If the fractional portion of number is .5 or greater, the argument is rounded to the next highest integer. If the fractional portion of number is less than .5, the argument is rounded to the next lowest integer.
Because round is a static method of Math, you always use it as Math.round(), rather than as a method of a Math object you created.
Examples
//Displays the value 20
document.write("The rounded value is " + Math.round(20.49))//Displays the value 21
document.write("<P>The rounded value is " + Math.round(20.5))//Displays the value -20
document.write("<P>The rounded value is " + Math.round(-20.5))//Displays the value -21
In server-side JavaScript, you can display the same output by calling the
document.write("<P>The rounded value is " + Math.round(-20.51))write function instead of using document.write.
sin
Returns the sine of a number.
| Method of |
Math
|
| Static | |
| Implemented in | Navigator 2.0, LiveWire 1.0 |
x | A number |
Description
The sin method returns a numeric value between -1 and 1, which represents the sine of the argument.
Because sin is a static method of Math, you always use it as Math.sin(), rather than as a method of a Math object you created.
Examples
The following function returns the sine of the variable x:
function getSine(x) {
If you pass
return Math.sin(x)
}getSine the value Math.PI/2, it returns 1.
See also
Math.acos, Math.asin, Math.atan, Math.atan2, Math.cos, Math.tan
sqrt
Returns the square root of a number.
| Method of |
Math
|
| Static | |
| Implemented in | Navigator 2.0, LiveWire 1.0 |
x | A number |
Description
If the value of number is outside the required range, sqrt returns 0.
Because sqrt is a static method of Math, you always use it as Math.sqrt(), rather than as a method of a Math object you created.
Examples
The following function returns the square root of the variable x:
function getRoot(x) {
If you pass
return Math.sqrt(x)
}getRoot the value 9, it returns 3; if you pass it the value 2, it returns 1.414213562373095.
tan
Returns the tangent of a number.
| Method of |
Math
|
| Static | |
| Implemented in | Navigator 2.0, LiveWire 1.0 |
x | A number |
Description
The tan method returns a numeric value that represents the tangent of the angle.
Because tan is a static method of Math, you always use it as Math.tan(), rather than as a method of a Math object you created.
Examples
The following function returns the tangent of the variable x:
function getTan(x) {
If you pass
return Math.tan(x)
}Math.PI/4 to getTan, it returns 0.9999999999999999.
See also
Math.acos, Math.asin, Math.atan, Math.atan2, Math.cos, Math.sin
Last Updated: 10/31/97 16:00:33