The second language, however, is a mature, full-featured, carefully constrained, object-based language, which does require more in-depth understanding. Used correctly, it can help web applications scale (increase their number of users) with little or no change to the application on the server. It can simplify web-site development and add a level of sophistication, making a good site appear even better to its visitors.
going to introduce you to both languages just described: the fun scripting
language, as well as the powerful object-oriented programming language.
Rewind to early 1995. Netscape had just hired Brendan Eich away from MicroUnity Systems Engineering, to take charge of the design and implementation of a new language. Tasked with making Navigator’s newly added Java support more accessible to non-Java programmers, Eich eventually decided that a loosely typed scripting language suited the environment and audience, namely the few thousand web designers and developers who needed to be able to tie into page elements (such as forms, or frames, or images) without a bytecode compiler or knowledge of object-oriented software design.
You can download a PDF of ECMA-262 at http://www.ecma-international.org/publications/standards/Ecma-262.htm. It’s not exciting reading, but it does make a good companion reference.
The second version of ECMA-262 was strictly a maintenance release. The third, and current, version was released in December 1999.
Table 1-1. Script support in browsers
|Browser||Script support||Documentation URL|
|Internet Explorer 6.x||ECMA-262 (v3) /JScript 5.6||http://msdn.microsoft.com/library/default.asp?url=/library/en-us/script56/html/1e9b3876-3d38-4fd8-8596-1bbfe2330aa9.asp|
|Internet Explorer 7.x (Windows XP)||ECMA-262 (v3) /JScript 5.6||http://msdn.microsoft.com/ie/|
|Safari 2.x on Tiger||ECMA-262 (v3)||http://developer.apple.com/documentation/AppleApplications/Conceptual/SafariJSProgTopics/index.html|
|Various wireless device browsers||Varies||Site that contains reference to several emulators and testing tools: http://www.wirelessdevnet.com/channels/printlinks.phtml?category=4|