HTMLCollection: length property

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

The HTMLCollection.length property returns the number of items in a HTMLCollection.

Value

An integer value representing the number of items in a HTMLCollection.

The length property is often useful in DOM programming. It's often used to test the length of a list, to see if it exists at all. It's also commonly used as the iterator in a for loop, as in this example.

js
// All the elements with the class ".test" in the document
const items = document.getElementsByClassName("test");

// For each test item in the list,
// append the entire element as a string of HTML
let gross = "";
for (let i = 0; i < items.length; i++) {
  gross += items[i].innerHTML;
}

// gross is now all the HTML for the test elements