JavaScript History and Versions

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This section provides a quick description of JavaScript language specification standards, ECMAScript, JavaScript, LiveScript, and JScript. and history of versions.

JavaScript has one specification and several dialects:

• ECMAScript - The official name of the JavaScript language specification, the ECMA-262 specification.
• JavaScript - The originating dialect of the ECMAScript language specification. JavaScript was implemented in Netscape.
• LiveScript - The predecessor of JavaScript. LiveScript was renamed to JavaScript in Netscape 3.0.
• JScript - The Microsoft dialect of the ECMAScript language specification. JScript was first implemented in Internet Explorer 3.0 browser released in August 1996.
• JScript .NET - The successor of JScript under Microsoft's .NET framework.

Here is a quick summary of JavaScript history and versions of its dialects:

1994   Netscape 1.0 
199?   Netscape 2.0/JavaScript 1.0   ECMA-262 Edition 1, 1997
1996   IE 3.0/JScript 1.0            ECMA-262 Edition 1, 1997
199?   Netscape 3.0/JavaScript 1.1   ECMA-262 Edition 1, 1997
1997   IE 4.0/JScript 3.0            ECMA-262 Edition 1, 1997
199?   Netscape 4.0/JavaScript 1.2   ECMA-262 Edition 1, 1997
1999   IE 5.0/JScript 5.0            ECMA-262 Edition 1, 1997
2000   Netscape 6.0/JavaScript 1.5   ECMA-262 Edition 3, 1999
2000   IE 5.5/JScript 5.5            ECMA-262 Edition 3, 1999
2001   IE 6.0/JScript 5.6            ECMA-262 Edition 3, 1999
2002   Netscape 7.0/JavaScript 1.5   ECMA-262 Edition 3, 1999
2004   FireFox 1.0                   ECMA-262 Edition 3, 1999
2006   IE 7.0/JScript ?              ECMA-262 Edition 3, 1999
2006   FireFox 2.0/JavaScript 1.7    ECMA-262 Edition 3, 1999
2007   Netscape 8.0/JavaScript ?     ECMA-262 Edition ?
2008   IE 8.0/JScript ?              ECMA-262 Edition ?
200?   FireFox 3.0/JavaScript 1.8    ECMA-262 Edition ?

The latest version of JavaScript specification is ECMA-262 Edition 3. So we should use it as the main reference to learn JavaScript.

Sections in This Chapter

JavaScript History and Versions

ECMAScript Language Specification

Automatic Semicolon Insertion to End Statements