11.1 Versions of JavaScript
The name JavaScript is owned by Netscape.
Microsoft's implementation of the language is
officially known as JScript, but very few people actually make a
distinction between JavaScript and JScript. Versions of JScript are
more or less compatible with the equivalent versions of JavaScript,
although JScript skipped a version and went directly from JavaScript
1.0 compatibility to JavaScript 1.2 compatibility.
JavaScript has been standardized
by ECMA (the organization formerly known as the European Computer
Manufacturers Association) and is on the fast track for
standardization by the International Standards Organization (ISO).
The relevant standards are ECMA-262 and, when standardized by ISO,
ISO-16262. These standards define a language officially known as
ECMAScript, which is approximately equivalent to JavaScript 1.1,
although not all implementations of JavaScript currently conform to
all details of the ECMA standard. The name ECMAScript is universally
regarded as ugly and cumbersome and was chosen precisely for this
reason: it favors neither Netscape's JavaScript nor
Microsoft's
JScript.
In this chapter, we universally use the term JavaScript to refer to
the scripting language. Where certain functionality is implemented
only by either Navigator or Internet Explorer, we've
noted that fact. When necessary, we use the term ECMA-262 to refer to
the standardized version of the language.
The following table specifies what versions of client-side JavaScript
are supported by various versions of Netscape Navigator and Microsoft
Internet Explorer:
|
|
2
|
JavaScript 1.0
| | |
3
|
JavaScript 1.1
|
JavaScript 1.0
| |
4
|
JavaScript 1.2; not fully ECMA-262 compliant prior to Version 4.5
|
JavaScript 1.2;EMCA-262 compliant
|
 | 
