Math

Math is a different from the other built-in objects because it cannot be used as a constructor to create objects. It's just a collection of static functions and constants. Some examples to illustrate the difference are as follows:

    > typeof Date.prototype; 
    "object" 
    > typeof Math.prototype; 
    "undefined" 
    > typeof String; 
    "function" 
    > typeof Math; 
    "object" 

Members of the Math object

Following are the members of the Math object:

Property/method	Description
Math.E Math.LN10 Math.LN2 Math.LOG2E Math.LOG10E Math.PI Math.SQRT1_2 Math.SQRT2	These are some useful math constants, all read-only. Here are their values: > Math.E; 2.718281828459045 > Math.LN10; 2.302585092994046 > Math.LN2; 0.6931471805599453 > Math.LOG2E; 1.4426950408889634 > Math.LOG10E; 0.4342944819032518 > Math.PI; 3.141592653589793 > Math.SQRT1_2; 0.7071067811865476 > Math.SQRT2; 1.4142135623730951
Math.acos(x) Math.asin(x) Math.atan(x) Math.atan2(y, x) Math.cos(x) Math.sin(x) Math.tan(x)	Trigonometric functions
Math.round(x) Math.floor(x) Math.ceil(x)	round() gives you the nearest integer, ceil() rounds up, and floor() rounds down: > Math.round(5.5); 6 > Math.floor(5.5); 5 > Math.ceil(5.1); 6
Math.max(num1, num2, num3, ...) Math.min(num1, num2, num3, ...)	max() returns the largest and min() returns the smallest of the numbers passed to them as arguments. If at least one of the input parameters is NaN, the result is also NaN: > Math.max(4.5, 101, Math.PI); 101 > Math.min(4.5, 101, Math.PI); 3.141592653589793
Math.abs(x)	Absolute value: > Math.abs(-101); 101 > Math.abs(101); 101
Math.exp(x)	Exponential function: Math.E to the power of x: > Math.exp(1) === Math.E; true
Math.log(x)	Natural logarithm of x: > Math.log(10) === Math.LN10; true
Math.sqrt(x)	Square root of x: > Math.sqrt(9); 3 > Math.sqrt(2) === Math.SQRT2; true
Math.pow(x, y)	x to the power of y: > Math.pow(3, 2); 9
Math.random()	Random number between 0 and 1 (including 0). > Math.random(); 0.8279076443185321 For an random integer in a range, say between 10 and 100: > Math.round(Math.random() * 90 + 10); 79