Tutorials Exercises Get Certified Services Menu
Log in
Sign Up Spaces Bootcamps

JS Reference

JS by Category JS by Alphabet


JS Array JS Boolean JS Classes JS Date JS Error JS Global JS JSON JS Math JS Number JS Object JS Operators JS Precedence JS RegExp JS Statements JS String JS TypedArray


Window Object Window Console Window History Window Location Window Navigator Window Screen


HTML Documents HTML Elements HTML Attributes HTML Collection HTML NodeList HTML DOMTokenList HTML Styles
alignContent alignItems alignSelf animation animationDelay animationDirection animationDuration animationFillMode animationIterationCount animationName animationTimingFunction animationPlayState background backgroundAttachment backgroundClip backgroundColor backgroundImage backgroundOrigin backgroundPosition backgroundRepeat backgroundSize backfaceVisibility border borderBottom borderBottomColor borderBottomLeftRadius borderBottomRightRadius borderBottomStyle borderBottomWidth borderCollapse borderColor borderImage borderImageOutset borderImageRepeat borderImageSlice borderImageSource borderImageWidth borderLeft borderLeftColor borderLeftStyle borderLeftWidth borderRadius borderRight borderRightColor borderRightStyle borderRightWidth borderSpacing borderStyle borderTop borderTopColor borderTopLeftRadius borderTopRightRadius borderTopStyle borderTopWidth borderWidth bottom boxShadow boxSizing captionSide caretColor clear clip color columnCount columnFill columnGap columnRule columnRuleColor columnRuleStyle columnRuleWidth columns columnSpan columnWidth counterIncrement counterReset cssFloat cursor direction display emptyCells filter flex flexBasis flexDirection flexFlow flexGrow flexShrink flexWrap font fontFamily fontSize fontStyle fontVariant fontWeight fontSizeAdjust height isolation justifyContent left letterSpacing lineHeight listStyle listStyleImage listStylePosition listStyleType margin marginBottom marginLeft marginRight marginTop maxHeight maxWidth minHeight minWidth objectFit objectPosition opacity order orphans outline outlineColor outlineOffset outlineStyle outlineWidth overflow overflowX overflowY padding paddingBottom paddingLeft paddingRight paddingTop pageBreakAfter pageBreakBefore pageBreakInside perspective perspectiveOrigin position quotes resize right scrollBehavior tableLayout tabSize textAlign textAlignLast textDecoration textDecorationColor textDecorationLine textDecorationStyle textIndent textOverflow textShadow textTransform top transform transformOrigin transformStyle transition transitionProperty transitionDuration transitionTimingFunction transitionDelay unicodeBidi userSelect verticalAlign visibility width wordBreak wordSpacing wordWrap widows zIndex

HTML Events

HTML Events HTML Event Objects HTML Event Properties HTML Event Methods

Web APIs

API Canvas API Console API Fetch API Fullscreen API Geolocation API History API MediaQueryList API Storage API Validation API Web

HTML Objects

<a> <abbr> <address> <area> <article> <aside> <audio> <b> <base> <bdo> <blockquote> <body> <br> <button> <canvas> <caption> <cite> <code> <col> <colgroup> <datalist> <dd> <del> <details> <dfn> <dialog> <div> <dl> <dt> <em> <embed> <fieldset> <figcaption> <figure> <footer> <form> <head> <header> <h1> - <h6> <hr> <html> <i> <iframe> <img> <ins> <input> button <input> checkbox <input> color <input> date <input> datetime <input> datetime-local <input> email <input> file <input> hidden <input> image <input> month <input> number <input> password <input> radio <input> range <input> reset <input> search <input> submit <input> text <input> time <input> url <input> week <kbd> <label> <legend> <li> <link> <map> <mark> <menu> <menuitem> <meta> <meter> <nav> <object> <ol> <optgroup> <option> <output> <p> <param> <pre> <progress> <q> <s> <samp> <script> <section> <select> <small> <source> <span> <strong> <style> <sub> <summary> <sup> <table> <tbody> <td> <tfoot> <th> <thead> <tr> <textarea> <time> <title> <track> <u> <ul> <var> <video>

Other References

CSSStyleDeclaration JS Conversion



A DOMTokenList is a set of space separated tokens.

A DOMTokenList can be accessed by index (starts at 0).

The length Property returns the number of tokens in a DOMTokenList.


The The classList Property of an HTML element represents a DOMTokenList.

DOMTokenList Properties and Methods

Name Description
add() Adds one or more tokens to the list
contains() Returns true if the list contains a class
entries() Returns an Iterator with key/value pairs from the list
forEach() Executes a callback function for each token in the list
item() Returns the token at a specified index
keys() Returns an Iterator with the keys in the list
length Returns the number of tokens in the list
remove() Removes one or more tokens from the list
replace() Replaces a token in the list
supports() Returns true if a token is one of an attribute's supported tokens
toggle() Toggles between tokens in the list
value Returns the token list as a string
values() Returns an Iterator with the values in the list


Add a "myStyle" class to an element:

Try it Yourself »

Remove the "myStyle" class from an element:

Try it Yourself »

Toggle "myStyle" on and off:

Try it Yourself »

More examples below.

Not an Array

A DOMTokenList is not an Array!

A DOMTokenList may look like an array, but it is not.

You can loop through a DOMTokenList and refer to its token with an index.

But you cannot use Array methods like push(), pop(), or join() on a DOMTokenList.

Add multiple classes to the an element:

element.classList.add("myStyle", "anotherClass", "thirdClass");
Try it Yourself »

Remove multiple classes from an element:

element.classList.remove("myStyle", "anotherClass", "thirdClass");
Try it Yourself »

Get the number of class names for an element:

let numb = element.classList.length;
Try it Yourself »

Get the class names of the "myDIV" element:

<div id="myDIV" class="myStyle anotherClass thirdClass">
<p>I am myDIV.</p>

const list = document.getElementById("myDIV").classList;
Try it Yourself »

Get the first class of an element:

let className = element.classList.item(0);
Try it Yourself »

Does an an element has a "myStyle" class?

let x = element.classList.contains("myStyle");
Try it Yourself »

Remove "anotherClass" if an element has a "myStyle" class.

if (element.classList.contains("mystyle")) {
Try it Yourself »

Toggle between classes to create a dropdown button:

document.getElementById("myBtn").onclick = function() {myFunction()};

function myFunction() {
Try it Yourself »

Create a sticky navigation bar:

// Get the navbar
const navbar = document.getElementById("navbar");

// Get the offset position of the navbar
const sticky = navbar.offsetTop;

// Add the sticky class to the navbar when you reach its scroll position
// Remove it when you leave the scroll position
function myFunction() {
  if (window.pageYOffset  >= sticky) {
  } else {
Try it Yourself »