A brief history of JavaScript

First, JavaScript introduction

A brief history of 1.1 JavaScript

JavaScript was born in 1995. Its primary purpose at the time was to handle some of the input validation operations previously held by the server-side language.

1.2 JavaScript implementation

A complete JavaScript implementation = Core (ECMAScript) + Document Object Model (DOM) + Browser object Model (BOM).

ECMAScript

ECMAScript is a scripting language that is standardized by the European Computer Manufacturers Association (ECMA) through ECMA-262 , defining only specifications and not defining implementations.

The latest edition is the 2009 ES5, ECMAScript3.1 became ECMAS-262 Fifth edition.

Document Object Model:

The Document Object Model (DOM) is a platform-neutral interface that allows programs and scripts to dynamically access and update the content, structure, and style of a document. ”

The DOM maps the entire page into a multi-tiered node structure. Each component in an HTML or XML page is a node of a certain type, allowing the DOM developer to modify its appearance and content for the first time without reloading the page.

The usual DOM is an application programming interface for XML that has been extended for HMTL.

The DOM standard is divided into 3 different parts:

• Core DOM-a standard model for any structured document
• XML DOM-a standard model for XML documents
• HTML DOM-A standard model for HTML documents

The HTML DOM defines the objects and properties of all HTML elements, as well as how to access them. in other words, the HTML DOM is the standard for how to get, modify, add, or delete HTML elements.

where the Document Object model is divided into three levels :

In 1998, the DOM1-class, the DOM1-class consists of two modules, the DOM core and Dom HTML, where the DOM core specifies how to map an XML-based document structure to simplify access and manipulation of any part of the document, Dom HTML modules are expanded on the basis of the DOM core, adding objects and methods for HTML .

DOM2 level in the original DOM on the basis of the expansion of the mouse and user interface events, scope, traverse (iterative Dom document method) and other subdivision modules, and through the object interface to add support for CSS,DOM2 class introduced a new module, The definition of many new types and new interfaces is also given.

The DOM3 scale further expands the DOM, introduces methods for loading and saving documents in a uniform manner, adds methods for validating documents, and extends the DOM core.

Browser object Model (Browser):

Provides a content-independent structure of objects that can interact with a browser window .

A BOM consists of multiple objects, which represent the window object of the browser windows as the top-level object of the BOM, and the other objects are child objects of that object.

1.3 JavaScript version

Currently javaScript2.0 has not been implemented, the highest version to javaScript1.8

A brief history of JavaScript