In JavaScript, DOM methods like getElementsByTagName() and getElementsByClassName() return a live collection of HTML elements called HTMLCollection.

HTMLCollection is an array-like object that represents a collection of HTML elements. It is live, meaning changes in the DOM are reflected in the collection automatically.

You can access items using index numbers or the item name.

• document.getElementsByTagName()
• document.getElementsByClassName()
• element.children

You can access individual elements using:

• collection[index]
• collection.item(index)

The children property returns an HTMLCollection of child elements (excluding text and comment nodes).