DOM

Provide a helper function that returns all siblings of an element.

Get all the child elements of an element

Select elements that match a tag name using the getElementsByTagName() method.

Select elements that match a class name using the getElementsByClassName method.

Get the parent node of an element by using the parentNode property of the element.

Select an element that matches the id using the getElementById() method.

Select elements that match a CSS selector using the querySeelctor() and querySelectorAll() methods.