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 |
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All number methods return a new value. They do not change the original variable. |
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