JavaScript basic Operations

1. What is DOM
Dom is the short name of the Document Object model, and its basic idea is to parse the structured document into a series of nodes, and then make a tree-like structure from these nodes. The final tree structure of all nodes has a canonical external interface to achieve the purpose of manipulating the document using the programming language, so that the DOM can be understood as a form of a document's transformation.
Strictly speaking, Dom is not a JavaScript, but manipulating the DOM is the most common task of JavaScript, and JavaScript is the most commonly used language for DOM manipulation.

2. Node
The smallest component of a DOM is called a node, and a document's tree structure is made up of various types of nodes.
The six main nodes are as follows:
1.Document document node entire document (Window.document)
Type of 2.DocumentType document type node document
3.Element element node HTML elements (e.g. Attributes of the 4.Attribute attribute node HTML element (e.g. class= "right")
Text that appears in a 5.Text text node HTML document
Fragment of a 6.DocumentFragment document fragment node document

3. Select Document elements
1. By ID:document.getElementById ("Idname")
2. Find the element by name or tag name: Getelementsbyname () method or getElementsByTagName () method, but if there are multiple
3. Querying and setting the attributes of an element: GetAttribute (), SetAttribute ()
4. Father node: The parent node of the current node can be manipulated by the ParentNode () method
5. Creating and Inserting Nodes: createelement (), AppendChild ()
Creating a node with the createelement () method
Inserting a node through the Appendelement () method
6. Deletion of nodes: RemoveChild ()

JavaScript basic Operations