Returns the specific node at the given zero-based index into the list.
Returns the specific node at the given zero-based index into the list. Returns null if the index is out of range.
MDN
Returns the specific node whose ID or, as a fallback, name matches the string specified by name.
Returns the specific node whose ID or, as a fallback, name matches the string specified by name. Matching by name is only done as a last resort, only in HTML, and only if the referenced element supports the name attribute. Returns null if no node exists by the given name.
MDN