JavaScript Learning notes-4

1. Document.getelementbytagname return is a nodelist, this nodelist and JS array very similar, can use subscript read, such as: array[0], but they also have different, The difference is that you cannot perform operations other than read, such as Push,pop, on NodeList.
2. NodeType judgment on DOM nodes often uses 1 for element nodes, 3 for text nodes, and 9 for document nodes (document root elements such as HTML), but this memory is too cumbersome to use document. Element_node,document. Text_node and Document.document_node instead.
3. getElementById is a unique method of document, and Getelementbytagname can be used by any tag element.

JavaScript Learning notes-4