Introduction to JavaScript-

JavaScript is an object-and event-driven, client-side scripting language that was originally designed to verify The correctness of HTML form input. Originated in the LiveScript language, finally Netscape and Sun will livescript named JavaScript,

the final JavaScript was submitted to the European Computer Manufacturers Association (ECMA), the neutral ECMA began the standardized scripting language Road, and name it ECMAScript. [Ek-ma-script]ecmascript ECMA International (formerly European Association of Computer manufacturers English name is european computer manufacturers association ) through ecma-262 standardized scripting programming language. This language is widely used on the World Wide Web, and it is often referred to as javascript jscript ecma-262 standard implementation and extension. ECMAScript is actually a syntactic and semantic standard for scripting . Latest version released 6 months ,ECMAScript 6 released the official version, namely ECMAScript.  

the composition of Javascript : Ecmscript( core ),bom,dom

(1) ECMAscript(European Computer Manufacturers Association) by ECMA-262 Standardized scripting programming language.

The main components are:

syntax, type, statement, keyword, reserved word, operator, object.

There are 6 versions of ECMA-262.

ECMAScript 1 1997 Month first edition

ECMAScript 2 1998 Month format amended to make it consistent with iso/iec16262 International Standards

ECMAScript 3 1999 Month strong regular expressions, better word chain processing, new control commands, exception handling, more explicit error definitions, formatting of number outputs and other changes

ECMAScript 4 not completed ... may be more explicit about the definition of the class, namespace, etc. ...

* 2004 6 months The European Association of Computer manufacturers published the ECMA-357 Standard, which is A extension of ECMAScript, It is also known as e4x(ECMAScript for XML).

ECMAScript 5 Month release

year 6 17 Day released.

(2)  bom (B rowser  O Span style= "Font-family:arial;letter-spacing:0;font-size:13px;background-color:rgb (255,255,255);" >bject  M Span style= "Font-family:arial;letter-spacing:0;font-size:13px;background-color:rgb (255,255,255);" >odel browser object model. The browser object model, which provides many objects for accessing the functionality of the browser. In fact, it provides a set of custom api

the BOM objects are:

Window object (Windows): The object is at the top of the object hierarchy and provides methods and properties for working with the Navigator window

Browser Object (navigator): provides information about the browser

Screen object: Provides user display detail information

Frame Object (frame): contains the layout information of the frame, and the window object corresponding to each frame

Location Object : provides methods and properties that work with the currently open URL , which is a static object

Historical Object (History): provides information about the history list

Document Object : contains objects that work with document elements that encapsulate these elements for use by programmers. Document objects are at the heart of the browser object model and play a key role in implementing Web page information interactions.

Support for cookies , like XMLHttpRequest and IE 's ActiveXObject such a custom object.

the core object of the BOM is window(top-level object).

The commonly used BOM APIs are:window---"document, Location ,navigator,screen .....

But the BOM does not conform to its own specifications. But slowly , the main specification of the BOM has been incorporated into the H5 .

(3) DOM(documentobject model). DOM is The standard of World Wide Web Consortium

The DOM can access and modify the content and structure of a document in a platform-independent and language way,and theDom maps the entire page to a file composed of hierarchical nodes. Is the method and the node that can access and manipulate the content of the Web page. The DOM tree can be formed according to the page elements .

The DOM standard is divided into 3 different parts:

Core DOM- a standard model for any structured document

XML DOM-Standard Model for XML documents:XML DOM is the standard for getting, changing, adding, or deleting XML elements

HTML DOM-a standard Model for HTML documents:HTML DOM is about how to get, modify, add, or delete HTML standard for c14> elements.

The DOM can be divided into 3 levels:

Level 1:1998 year . consists of the Dom core and the Dom HTML module. the level 1 DOM targets only the mapping document structure.

level: 2 dom dhtml long-term support for mouse and user interface events), scope, traverse (repeat dom "and cascading style sheets ( css dom 1 xml namespace.

Level 3: level 3 Dom further expands the Dom by introducing a unified way to load and save document and document validation methods . The DOM3 contains a new module called "DOM load and save".

Books that learn JavaScript are:

(1) JavaScript advanced programming

(2) JavaScript language essence

(3) JavaScript revelation

(4) JavaScript authoritative guide , etc.

Introduction to JavaScript-