JavaScript HTML DOM Node List

A node list is a collection of nodes

HTML DOM Node List

The getElementsByTagName() method returns a node list. A node list is an array-like collection of nodes.

The following code selects all <p> nodes in a document:


var x = document.getElementsByTagName("p");

The nodes can be accessed by an index number. To access the second <p> node you can write:

y = x[1];
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Note: The index starts at 0.

HTML DOM Node List Length

The length property defines the number of nodes in a node list:


var myNodelist = document.getElementsByTagName("p");
document.getElementById("demo").innerHTML = myNodelist.length;
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Example explained:

  1. Get all <p> elements in a node list
  2. Display the length of the node list

The length property is useful when you want to loop through the nodes in a node list:


Change the background color of all <p> elements in a node list:

var myNodelist = document.getElementsByTagName("p");
var i;
for (i = 0; i < myNodelist.length; i++) {
    myNodelist[i].style.backgroundColor = "red";
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Note A node list is not an array!

A node list may look like an array, but it is not. You can loop through the node list and refer to its nodes like an array. However, you cannot use Array Methods, like valueOf() or join() on the node list.