developer.mozilla.org Open in urlscan Pro
2600:9000:225e:c800:2:eb5:8c00:93a1  Public Scan

Form analysis
1 forms found in the DOM

/en-US/search

<form action="/en-US/search" role="search" aria-haspopup="listbox" aria-owns="top-nav-search-menu" aria-expanded="false" class="search-form search-widget" id="top-nav-search-form"><label id="top-nav-search-label" for="top-nav-search-input"
    class="visually-hidden">Search MDN</label><input id="top-nav-search-input" aria-autocomplete="list" aria-controls="top-nav-search-menu" aria-labelledby="top-nav-search-label" autocomplete="off" type="search" class="search-input-field" name="q"
    placeholder="   " required="" value=""><button type="button" class="button action has-icon clear-search-button"><span class="button-wrap"><span class="icon icon-cancel "></span><span class="visually-hidden">Clear search
        input</span></span></button><button type="submit" class="button action has-icon search-button"><span class="button-wrap"><span class="icon icon-search "></span><span class="visually-hidden">Search</span></span></button>
  <div id="top-nav-search-menu" role="listbox" aria-labelledby="top-nav-search-label"></div>
</form>

Text Content

 * Skip to main content
 * Skip to search
 * Skip to select language

MDN Plus now available in your country! Support MDN and make it your own. Learn
more ✨


MDN Web DocsOpen main menu
 * ReferencesReferences
   * Overview / Web Technology
     
     Web technology reference for developers
   
   * HTML
     
     Structure of content on the web
   
   * CSS
     
     Code used to describe document style
   
   * JavaScript
     
     General-purpose scripting language
   
   * HTTP
     
     Protocol for transmitting web resources
   
   * Web APIs
     
     Interfaces for building web applications
   
   * Web Extensions
     
     Developing extensions for web browsers
   
   * Web Technology
     
     Web technology reference for developers
 * GuidesGuides
   * Overview / MDN Learning Area
     
     Learn web development
   
   * MDN Learning Area
     
     Learn web development
   
   * HTML
     
     Learn to structure web content with HTML
   
   * CSS
     
     Learn to style content using CSS
   
   * JavaScript
     
     Learn to run scripts in the browser
   
   * Accessibility
     
     Learn to make the web accessible to all
 * MDN PlusMDN Plus
   * Overview
     
     A customized MDN experience
   
   * 
     New feature
     Updates
     
     All browser compatibility updates at a glance
   
   * Documentation
     
     Learn how to use MDN Plus
   
   * FAQ
     
     Frequently asked questions about MDN Plus

Search MDNClear search inputSearch

Theme
 * Already a subscriber?
 * Get MDN Plus

 1. References
 2. JavaScript
 3. JavaScript
 4. Standard built-in objects
 5. Number
 6. Number.isInteger()

Article Actions
 * English (US)


IN THIS ARTICLE

 * Try it
 * Syntax
 * Description
 * Examples
 * Specifications
 * Browser compatibility
 * See also

RELATED TOPICS

 1.  Standard built-in objects
 2.  Number
 3.  Properties
      1. Number.EPSILON
      2. Number.MAX_SAFE_INTEGER
      3. Number.MAX_VALUE
      4. Number.MIN_SAFE_INTEGER
      5. Number.MIN_VALUE
      6. Number.NaN
      7. Number.NEGATIVE_INFINITY
      8. Number.POSITIVE_INFINITY

 4.  Methods
      1.  Number.isFinite()
      2.  Number.isInteger()
      3.  Number.isNaN()
      4.  Number.isSafeInteger()
      5.  Number.parseFloat()
      6.  Number.parseInt()
      7.  Number.prototype.toExponential()
      8.  Number.prototype.toFixed()
      9.  Number.prototype.toLocaleString()
      10. Number.prototype.toPrecision()
      11. Number.prototype.toString()
      12. Number.prototype.valueOf()

 5.  Inheritance:
 6.  Function
 7.  Properties
      1. Non-standard Deprecated Function.prototype.arguments
      2. Non-standard Deprecated Function.prototype.caller
      3. Non-standard Function.prototype.displayName
      4. Function.prototype.length
      5. Function.prototype.name
      6. Function.prototype.prototype

 8.  Methods
      1. Function.prototype.apply()
      2. Function.prototype.bind()
      3. Function.prototype.call()
      4. Function.prototype.toString()

 9.  Object
 10. Properties
      1. Object.prototype.constructor
      2. Deprecated Object.prototype.__proto__

 11. Methods
      1.  Deprecated Object.prototype.__defineGetter__()
      2.  Deprecated Object.prototype.__defineSetter__()
      3.  Deprecated Object.prototype.__lookupGetter__()
      4.  Deprecated Object.prototype.__lookupSetter__()
      5.  Object.prototype.hasOwnProperty()
      6.  Object.prototype.isPrototypeOf()
      7.  Object.prototype.propertyIsEnumerable()
      8.  Object.setPrototypeOf()
      9.  Object.prototype.toLocaleString()
      10. Object.prototype.toString()
      11. Object.prototype.valueOf()


IN THIS ARTICLE

 * Try it
 * Syntax
 * Description
 * Examples
 * Specifications
 * Browser compatibility
 * See also


NUMBER.ISINTEGER()

The Number.isInteger() method determines whether the passed value is an integer.


TRY IT




SYNTAX

Number.isInteger(value)


Copy to Clipboard


PARAMETERS

value

The value to be tested for being an integer.


RETURN VALUE

The boolean value true if the given value is an integer. Otherwise false.


DESCRIPTION

If the target value is an integer, return true, otherwise return false. If the
value is NaN or Infinity, return false. The method will also return true for
floating point numbers that can be represented as integer. It will always return
false if the value is not a number.

Note that some number literals, while looking like non-integers, actually
represent integers — due to the precision limit of ECMAScript floating-point
number encoding (IEEE-754). For example, 5.0000000000000001 only differs from 5
by 1e-16, which is too small to be represented. (For reference, Number.EPSILON
stores the distance between 1 and the next representable floating-point number
greater than 1, and that is about 2.22e-16.) Therefore, 5.0000000000000001 will
be represented with the same encoding as 5, thus making
Number.isInteger(5.0000000000000001) return true.

In a similar sense, numbers around the magnitude of Number.MAX_SAFE_INTEGER will
suffer from loss of precision and make Number.isInteger return true even when
it's not an integer. (The actual threshold varies based on how many bits are
needed to represent the decimal — for example,
Number.isInteger(4500000000000000.1) is true, but
Number.isInteger(4500000000000000.5) is false.)


EXAMPLES




USING ISINTEGER

Number.isInteger(0); // true
Number.isInteger(1); // true
Number.isInteger(-100000); // true
Number.isInteger(99999999999999999999999); // true

Number.isInteger(0.1); // false
Number.isInteger(Math.PI); // false

Number.isInteger(NaN); // false
Number.isInteger(Infinity); // false
Number.isInteger(-Infinity); // false
Number.isInteger("10"); // false
Number.isInteger(true); // false
Number.isInteger(false); // false
Number.isInteger([1]); // false

Number.isInteger(5.0); // true
Number.isInteger(5.000000000000001); // false
Number.isInteger(5.0000000000000001); // true, because of loss of precision
Number.isInteger(4500000000000000.1); // true, because of loss of precision


Copy to Clipboard


SPECIFICATIONS

SpecificationECMAScript Language Specification
# sec-number.isinteger


BROWSER COMPATIBILITY

Report problems with this compatibility data on GitHub

desktopmobileserver
Chrome

Edge

Firefox

Opera

Safari

Chrome Android

Firefox for Android

Opera Android

Safari on iOS

Samsung Internet

WebView Android

Deno

Node.js

isInteger
Full support
Chrome34
Toggle history
Full support
Edge12
Toggle history
Full support
Firefox16
Toggle history
Full support
Opera21
Toggle history
Full support
Safari9
Toggle history
Full support
Chrome Android34
Toggle history
Full support
Firefox for Android16
Toggle history
Full support
Opera Android21
Toggle history
Full support
Safari on iOS9
Toggle history
Full support
Samsung Internet2.0
Toggle history
Full support
WebView Android37
Toggle history
Full support
Deno1.0
Toggle history
Full support
Node.js0.12.0
Toggle history


LEGEND

Tip: you can click/tap on a cell for more information.

Full supportFull support
The compatibility table on this page is generated from structured data. If you'd
like to contribute to the data, please check out
https://github.com/mdn/browser-compat-data and send us a pull request.


SEE ALSO

 * Polyfill of Number.isInteger in core-js
 * The Number object it belongs to.


FOUND A PROBLEM WITH THIS PAGE?

 * Edit on GitHub
 * Source on GitHub
 * Report a problem with this content on GitHub
 * Want to fix the problem yourself? Learn how to contribute!

Last modified: Dec 13, 2022, by MDN contributors

MDN logo

Your blueprint for a better internet.

 * MDN on Twitter
 * MDN on GitHub


MDN

 * About
 * Hacks Blog
 * Careers


SUPPORT

 * Product help
 * Report an issue


OUR COMMUNITIES

 * MDN Community
 * MDN Forum
 * MDN Chat


DEVELOPERS

 * Web Technologies
 * Learn Web Development
 * MDN Plus

Mozilla logo
 * Website Privacy Notice
 * Cookies
 * Legal
 * Community Participation Guidelines

Visit Mozilla Corporation’s not-for-profit parent, the Mozilla Foundation.
Portions of this content are ©1998–2022 by individual mozilla.org contributors.
Content available under a Creative Commons license.