Sergi Oca7,981 Points
Understanding the difference between an HTMLCollection and a NodeList.
So in this video I realized, querySelectorAll returns a "nodeList", while getElementsByTagName (didn't check-ByClassName but I assume it's the same) returns an HTML Collection. I have read the official explanation and I don't really understand it. Is this important to understand? Is there a major difference between the two?
The most simplest answer is that both a NodeList and HTMLCollection are collections of DOM nodes. The difference is that while a NodeList can contain any node type, the HTMLCollection is going to only to contain any node Element.
So what is the difference between a node element and a node type?
Nodes: in the DOM, everything is a node and every node is an object. The name node is used as a generic term, for everything.
Element: is one specific type of node. It can be a list item, a div, the body, the window, whatever, but its a specific type.
Now we can see what the difference between a nodeList is and what a node element is:
By the way this is an awesome question!
Steven Parker203,124 Points
HTMLCollection and NodeList differ in potential contents and available methods.
An HTMLCollection should contain only elements, has a namedItem method, and allows item indexing by number or name.
A NodeList can contain elements along with other types of nodes (such as text blocks), and the items can only be indexed by number.
So they are very similar, but while a NodeList could possibly contain only elements, you could not use the namedItem method on it, or index into it using names as indices.