NodeList objects are collections of nodes, usually returned by properties such as Node.childNodes and methods such as document.querySelectorAll().

Although NodeList is not an Array, it is possible to iterate over it with forEach(). It can also be converted to a real Array using Array.from().

However, some older browsers have not implemented NodeList.forEach() nor Array.from(). This can be circumvented by using Array.prototype.forEach() — see this document's Example.

In some cases, the NodeList is live, which means that changes in the DOM automatically update the collection. For example, Node.childNodes is live:

var parent = document.getElementById('parent');
var child_nodes = parent.childNodes;
console.log(child_nodes.length); // let's assume "2"
parent.appendChild(document.createElement('div'));
console.log(child_nodes.length); // outputs "3"

In other cases, the NodeList is static, where any changes in the DOM does not affect the content of the collection. document.querySelectorAll() returns a static NodeList.

It's good to keep this distinction in mind when you choose how to iterate over the items in the NodeList, and if you should cache the list's length.

Properties

NodeList.length
The number of nodes in the NodeList.

Methods

NodeList.item()
Returns an item in the list by its index, or null if the index is out-of-bounds.
An alternative to accessing nodeList[i] (which instead returns  undefined when i is out-of-bounds). This is mostly useful for non-JavaScript languages DOM implementations.
NodeList.entries()
Returns an iterator, allowing code to go through all key/value pairs contained in the collection. (In this case, the keys are numbers starting from 0 and the values are nodes.)
NodeList.forEach()
Executes a provided function once per NodeList element, passing the element as an argument to the function.
NodeList.keys()
Returns an iterator, allowing code to go through all the keys of the key/value pairs contained in the collection. (In this case, the keys are numbers starting from 0.)
NodeList.values()
Returns an iterator allowing code to go through all values (nodes) of the key/value pairs contained in the collection.

Example

It's possible to loop over the items in a NodeList using a for loop:

for (var i = 0; i < myNodeList.length; i++) {
  var item = myNodeList[i];
}

Don't use for...in or for each...in to enumerate the items in NodeLists, since they will also enumerate its length and item properties and cause errors if your script assumes it only has to deal with element objects. Also, for..in is not guaranteed to visit the properties in any particular order.

for...of loops will loop over NodeList objects correctly:

var list = document.querySelectorAll('input[type=checkbox]');
for (var checkbox of list) {
  checkbox.checked = true;
}

Recent browsers also support iterator methods (forEach()) as well as entries(), values(), and keys().

There is also an Internet Explorer-compatible way to use Array.prototype.forEach for iteration:

var list = document.querySelectorAll('input[type=checkbox]');
Array.prototype.forEach.call(list, function (checkbox) {
  checkbox.checked = true;
});

Specifications

Specification Status Comment
DOM
The definition of 'NodeList' in that specification.
Living Standard  
Document Object Model (DOM) Level 3 Core Specification
The definition of 'NodeList' in that specification.
Obsolete  
Document Object Model (DOM) Level 2 Core Specification
The definition of 'NodeList' in that specification.
Obsolete  
Document Object Model (DOM) Level 1 Specification
The definition of 'NodeList' in that specification.
Obsolete Initial definition.

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidEdge MobileFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
Basic supportChrome Full support YesEdge Full support YesFirefox Full support YesIE Full support YesOpera Full support YesSafari Full support YesWebView Android Full support YesChrome Android Full support YesEdge Mobile Full support YesFirefox Android Full support YesOpera Android Full support YesSafari iOS Full support YesSamsung Internet Android Full support Yes
lengthChrome Full support 1Edge Full support 12Firefox ? IE ? Opera ? Safari ? WebView Android Full support YesChrome Android Full support YesEdge Mobile ? Firefox Android ? Opera Android ? Safari iOS ? Samsung Internet Android Full support Yes
entriesChrome Full support 51Edge Full support 16Firefox Full support 50IE No support NoOpera Full support 38Safari Full support 10WebView Android Full support 51Chrome Android Full support 51Edge Mobile ? Firefox Android Full support 50Opera Android ? Safari iOS Full support 10Samsung Internet Android Full support 5.0
forEachChrome Full support 51Edge Full support 16Firefox Full support 50IE No support NoOpera Full support 38Safari Full support 10WebView Android Full support 51Chrome Android Full support 51Edge Mobile ? Firefox Android Full support 50Opera Android ? Safari iOS Full support 10Samsung Internet Android Full support 5.0
itemChrome Full support 1Edge Full support 12Firefox ? IE ? Opera ? Safari ? WebView Android Full support YesChrome Android Full support YesEdge Mobile ? Firefox Android ? Opera Android ? Safari iOS ? Samsung Internet Android Full support Yes
keysChrome Full support 51Edge Full support 16Firefox Full support 50IE No support NoOpera Full support 38Safari Full support 10WebView Android Full support 51Chrome Android Full support 51Edge Mobile ? Firefox Android Full support 50Opera Android ? Safari iOS Full support 10Samsung Internet Android Full support 5.0
valuesChrome Full support 51Edge Full support 16Firefox Full support 50IE No support NoOpera Full support 38Safari Full support 10WebView Android Full support 51Chrome Android Full support 51Edge Mobile ? Firefox Android Full support 50Opera Android ? Safari iOS Full support 10Samsung Internet Android Full support 5.0

Legend

Full support  
Full support
No support  
No support
Compatibility unknown  
Compatibility unknown