The HTMLCollection Object
The getElementsByTagName() method returns an HTMLCollection object.
An HTMLCollection object is an array-like list (collection) of HTML elements.
The following code selects all <p> elements in a document:
Example
const myCollection = document.getElementsByTagName("p");
The elements in the collection can be accessed by an index number.
To access the second <p> element you can write:
myCollection[1]
Note: The index starts at 0.
HTML HTMLCollection Length
The length property defines the number of elements in an HTMLCollection:
Example
myCollection.length
The length property is useful when you want to loop through the elements in a collection:
Example
Change the text color of all <p> elements:
const myCollection = document.getElementsByTagName("p");
for (let i = 0; i < myCollection.length; i++) {
myCollection[i].style.color = "red";
}