What is javascript node

Javascript nodes refer to all content in the page, including tags, attributes, and text. The methods for obtaining JavaScript element nodes are: 1. getElementById() method; 2. getElementsByClassName() method, etc.

The operating environment of this article: Windows 7 system, javascript version 1.8.5, DELL G3 computer

The nodes in JavaScript are all in the page The content (label, attribute, text (text, newline, space, carriage return)), Node.

Our commonly used node labels:

• Element node (label)

• Text node

• Attribute node (attribute in label)

Get

element of the node There are many ways to get nodes

• Document.getElementById()

• Document.getElementsByClassName()

• Document.getElementsByTagName()

• Document.querySelector()

• Document.querySelectorAll()

Getting attribute nodes

• Element.attributes Gets the set of all attributes on the element

• Element.setAttribute("Attribute name", "Attribute value") Set attributes and attribute values ​​​​to elements

• Element.getAttribute("Attribute name") Method to get attribute values

• Element.removerAttribute("attribute") deletes the attribute

Text node

There is no way to get it, no meaning

Get the child of the element Node

Element.childNodes This attribute is compatible. Standard browsers will obtain text nodes, but lower version browsers will not. Therefore, it is recommended to use the children attribute to obtain a single child node.

Get the first child node:

标准下 　　元素.firstElementChild
非标准下　  元素.firstChild

Compatible writing method

var list=document.getElementById("list")
var fist=listElementChild||list.fistChild
console.log(fist)

Get the last child node

Element.lastElementChild Element.lastChild

Getting a sibling node

Element.previousSibling　Element.prevElementSibling

Getting the next sibling node

Element.nextSibling　Element.nextElementSibling

Get the parent node

Element.parentNode has no compatibility

Element.parentNode.parentNode

Distinguish between offsetparent and parentNode

DOM2 Create node

1. Method to generate node document. createElement ("div")

2. Method of inserting nodes

Parent node.appendChild(new node)

Insert a new node after the child node of the parent node

3. Insert a new node at the specified position

(1) Parent element.insetBefore (new node, in front of whom) Insert the new node in front of the specified element

4. Delete element node parent element.removerChild()

[Recommended learning: js basic tutorial】

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