What parts does javascript consist of?

Javascript is composed of 3 parts, namely: 1. ECMAScript core part; 2. DOM document object model part; 3. BOM browser object model part; these three parts describe the syntax and syntax of the language respectively. Basic objects, methods and interfaces for processing web page content, and methods and interfaces for interacting with browsers.

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

JavaScript consists of three parts. They are core (ECMAScript), Document Object Model (DOM), and Browser Object Model (BOM). These three parts describe the syntax and basic objects of the language, methods and interfaces for processing web content, and methods and interfaces for interacting with browsers.

1.ECMAScript (Core)

Note:

1. ECMAScript has no dependency on the web browser. The browser is just the host for the ECMAScript implementation. One of the environments

2. What is defined is only the basics of the language, such as some grammar, types, statements, keywords, reserved words, operators, objects...

3. The host environment provides The basic implementation and extension of the language, such as DOM

4, other host environments

Node: Server-side JavaScript platform

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2. DOM (Document Object Model)
1. Function

(1) Map the entire page into a multi-layer node structure

(2) Then provide a Methods for adding, deleting, modifying and checking these nodes (content)

2. DOM level

(1)DOM1

• How DOM Core maps based on XML Document structure

• DOM html Added objects and methods for html

(2)DOM2

Expanded the mouse And user interface events, scope, traversal and other subdivision modules add support for css through the object interface.

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The details are as follows:

• DOM view: defines tracking different document views Interface

• DOM event: defines the interface for events and event processing

• DOM style: defines the interface for operating element styles based on css

• DOM traversal and scope: a. Defines the interface for traversing and operating the document tree b. Adds a new method to verify the document

( 3) DOM3

Introduces a method to load and save documents in a unified way

3. Note

An application programming interface targeted at XML but extended for HTML (API), not just for JavaScript, many other languages ​​also implement DOM. zhou Brand Design Company https://www.houdianzi.comPPT template download collection https://redbox.wode007.com

三.BOM (Browser Object Model)

1. Function

• Processing browser windows and frames

• For JS extension for browser operation

2. Specific functions

• ##Function to pop up a new browser window

• Functions for moving, zooming and closing the browser window

• Navigator object that provides browser details

• Provides browsing The location object with detailed information about the page loaded by the server

• The screen object that provides detailed information about the user's monitor resolution

• Support for cookies

• XMLHttpRequest -- ActiveXObject

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