The Math object is a top-level, built-in JavaScript object which can be accessed without using a constructor or calling a method. It also has static properties and methods for mathematical constants and functions. This means that you can refer to, say, the constant PI as Math.PI, and you can call the Tangent function with Math.tan(x). All constants are defined as precision real numbers in JavaScript.
len = Math.tan(theta) * adj
To illustrate this how to call the static methods of Math, this example calculates the length of the side of a right-angled triangle opposite the angle Theta.
with(Math)
{
a = 28.27
adj = sqrt(a/PI)
len = adj * tan(1.1071)
}
When using several Math constants and methods, it is often more convenient to use the with statement to avoid having to repeatedly type the word Math.
Syntax: Object.constructor
This specifies a function to create an object's property and is inherited by all objects from their prototype.
Syntax: Math.E
This property is the base of natural logarithms (e, approximately 2.7183)
Syntax: Math.LN10
This property is the natural logarithm of 10, (approximately 2.3026).
Syntax: Math.LN2
This property is the natural logarithm of 2, which is approximately 0.6931.
Syntax: Math.LOG10E
This property is the base 10 logarithm of E (approximately 0.4343).
Syntax: Math.LOG2E
This property is the base 2 logarithm of E (approximately 1.4427).
Syntax: Math.PI
This property is the ratio of the circuference of a circle to its diameter (approximately 3.1416).
Syntax: Object.prototype.name = value
This allows the addition of properties and methods to any object.
Syntax: Math.SQRT1_2
This property is the value of 1 divided by the square root of 2 and is approximately equal to 0.7071.
Syntax: Math.SQRT2
This property is the square root of 2 (approximately 1.4142).
Syntax: Math.abs(x)
This method returns the absolute value of a number.
Syntax: Math.acos(x)
This method returns the arccosine of a number as a numeric value between 0 and PI radians. Passing it a value for 'x' which is outsite the range -1 to 1 will cause the Netscape browser to return NaN, and the Internet Explorer browser to return an error message. Passing it -1 will return the value of PI.
Syntax: Math.asin(x)
This method returns the arcsine of a number as a numeric value between
-PI/2 and PI/2 radians. Passing it a value for 'x' which is outsite
the range -1 to 1 will cause the Netscape browser to return NaN,
and the Internet Explorer browser to return an error message. Passing
it 1 will return the value of PI/2.
Syntax: Math.atan(x)
atan2 Method
This method returns the arctangent of the quotient of its arguments.
Syntax: Math.atan2(y, x)
This method returns the arctangent of a number as a numeric value between -PI/2 and PI/2 radians.
Syntax: Math.ceil(x)
This method returns an integer equal to, or the next integer greater than, the number passed to it. Hence, if you passed it 3.79, it would return 4, and passing it -3.79 would return -3.
Syntax: Math.cos(x)
This method returns the cosine of a number, which will be a numeric value between -1 and 1.
Syntax: Object.eval(string)
The eval method is deprecated as a method of Object, but is still used as a high level function. It evaluates a string of JavaScript in the context of an object.
Syntax: Math.exp(x)
This method returns the value of Ex where E is Euler's constant and x is the argument passed to it.
Syntax: Math.floor(x)
This method returns an integer equal to, or the next integer less than, the number passed to it. Hence, if you passed it 3.79, it would return 3, and passing it -3.79 would return -4.
Syntax: Math.log(x)
This method returns the natural logarithm (base E) of a number. If you pass the log method the number 0, the Netscape browser will return -Infinity, and with an argument of a negative number NaN. In both these cases Internet Explorer returns an error message.
Syntax: Math.max(x, y)
This method returns the greater of the two numbers passed to it as arguments. Hence, if you passed it the numbers 9 and 11, it would return 11, whereas passing it -9 and -11 returns -9.
Syntax: Math.min(x, y)
This method returns the lesser of the two numbers passed to it as arguments. Hence, if you passed it the numbers 9 and 11, it would return 9, whereas passing it -9 and -11 returns -11.
Syntax: Math.pow(x, y)
This method returns the value of x to the power of y (xy), where x is the base, and y is the exponent.
Syntax: Math.random()
This method takes no arguments and returns a pseudo-random number between 0 and 1. The random number generator is seeded from the current time.
Syntax: Math.round(x)
This method is used to round a number to the nearest integer. If the fractional portion of the number is .5 or higher, then the number is rounded up, otherwise it is rounded down.
Syntax: Math.sin(x)
This method is used to return the sine of its argument, which will be a number between -1 and 1.
Syntax: Math.sqrt(x)
This method returns the square root of a number. If that number is negative, then the Netscape browser returns the value of NaN, whereas the Internet Explorer browser returns an Error message.
Syntax: Math.tan(x)
This method returns a number representing the tangent of an angle.
Syntax: Object.toSource()
The toSource method returns a literal representing the source code of an object. This can then be used to create a new object.
Syntax: Object.toString()
The toString method returns a string representing a specified object.
Syntax: Object.unwatch(property)
This method removes a watchpoint set for an object and property name with the watch method.
Syntax: Object.valueOf()
This method returns a primitive value for a specified object.
Syntax: Object.watch(property, handlerfunction)
This method adds a watchpoint to a property of the object.