| Version | Description |
|---|---|
| JavaScript 1.0 | The original version of the language. It was buggy and is now essentially obsolete. Implemented by Netscape 2. |
| JavaScript 1.1 | Introduced a true Array object; most serious bugs resolved. Implemented by Netscape 3. |
| JavaScript 1.2 | Introduced the switch statement, regular expressions, and a number of other features. Almost compliant with ECMA v1, but has some incompatibilities. Implemented by Netscape 4. |
| JavaScript 1.3 | Fixed incompatibilities of JavaScript 1.2. Compliant with ECMA v1. Implemented by Netscape 4.5. |
| JavaScript 1.4 | Implemented only in Netscape server products. |
| JavaScript 1.5 | Introduced exception handling. Compliant with ECMA v3. Implemented by Mozilla and Netscape 6. |
| JScript 1.0 | Roughly equivalent to JavaScript 1.0. Implemented by early releases of IE 3. |
| JScript 2.0 | Roughly equivalent to JavaScript 1.1. Implemented by later releases of IE 3. |
| JScript 3.0 | Roughly equivalent to JavaScript 1.3. Compliant with ECMA v1. Implemented by IE 4. |
| JScript 4.0 | Not implemented by any web browser. |
| JScript 5.0 | Supported exception handling. Partially compliant with ECMA v3. Implemented by IE 5. |
| JScript 5.5 | Roughly equivalent to JavaScript 1.5. Fully compliant with ECMA v3. Implemented by IE 5.5 and IE 6. (IE 6 actually implements JScript 5.6, but 5.6 is not different from 5.5 in any way that is relevant to client-side JavaScript programmers.) |
| ECMA v1 | The first standard version of the language. Standardized the basic features of JavaScript 1.1 and added a few new features. Did not standardize the switch statement or regular expression support. Conformant implementations are JavaScript 1.3 and JScript 3.0. |
| ECMA v2 | A maintenance release of the standard that included clarifications but defined no new features. |
| ECMA v3 | Standardized the switch statement, regular expressions, and exception handling. Conformant implementations are JavaScript 1.5 and JScript 5.5. |