HTMLCollection: length property

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


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.

// 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


DOM Standard
# ref-for-dom-htmlcollection-length①

Browser compatibility

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