JavaScript Number Reference
JavaScript Numbers
JavaScript has only one type of number.
Numbers can be written with, or without, decimals:
Example
var x = 3.14; // A number with decimals
var y = 34; // A number without decimals
Extra large or extra small numbers can be written with scientific (exponent) notation:
Example
var x = 123e5; // 12300000
var y = 123e-5; // 0.00123
For a tutorial about JavaScript numbers, read our JavaScript Number Tutorial.
Number Properties
Property | Description |
---|---|
constructor | Returns the function that created JavaScript's Number prototype |
MAX_VALUE | Returns the largest number possible in JavaScript |
MIN_VALUE | Returns the smallest number possible in JavaScript |
NEGATIVE_INFINITY | Represents negative infinity (returned on overflow) |
NaN | Represents a "Not-a-Number" value |
POSITIVE_INFINITY | Represents infinity (returned on overflow) |
prototype | Allows you to add properties and methods to an object |
Number Methods
Method | Description |
---|---|
isFinite() | Checks whether a value is a finite number |
isInteger() | Checks whether a value is an integer |
isNaN() | Checks whether a value is Number.NaN |
isSafeInteger() | Checks whether a value is a safe integer |
toExponential(x) | Converts a number into an exponential notation |
toFixed(x) | Formats a number with x numbers of digits after the decimal point |
toPrecision(x) | Formats a number to x length |
toString() | Converts a number to a string |
valueOf() | Returns the primitive value of a number |