JavaScript is the name of Netscape Communications Corporation’s and now the Mozilla Foundation’s implementation of the ECMAScript standard, a scripting language based on the concept of prototype-based programming. The language is best known for its use in websites (as client-side JavaScript), but is also used to enable scripting access to objects embedded in other applications.
Despite the name, JavaScript is only distantly related to the Java programming language, the main similarity being their common debt to the C syntax. Semantically, JavaScript syntax has far more in common with the Self programming language.
JavaScript is a registered trademark of Sun Microsystems, Inc. It was used under license for technology invented and implemented by Netscape Communications and current entities such as the Mozilla Foundation.
Ajax, shorthand for Asynchronous JavaScript and XML, is a web development technique for creating interactive web applications. The intent is to make web pages feel more responsive by exchanging small amounts of data with the server behind the scenes, so that the entire web page does not have to be reloaded each time the user requests a change. This is meant to increase the web page’s interactivity, speed, and usability.
The Ajax technique uses a combination of:
XHTML (or HTML) and CSS, for marking up and styling information.
The DOM accessed with a client-side scripting language, especially ECMAScript implementations such as JavaScript and JScript, to dynamically display and interact with the information presented.
The XMLHttpRequest object is used to exchange data asynchronously with the web server. In some Ajax frameworks and in certain situations, an IFrame object is used instead of the XMLHttpRequest object to exchange data with the web server, and in other implementations, dynamically added <script> tags may be used.
XML is sometimes used as the format for transferring data between the server and client, although any format will work, including preformatted HTML, plain text, JSON and even EBML. These files may be created dynamically by some form of server-side scripting.
Like DHTML, LAMP and SPA, Ajax is not a technology in itself, but a term that refers to the use of a group of technologies.
Creme:
MiniAjax!
ajax dhtml and javascript librarie
script.aculo.us
‘Web 2.0’ encapsulates a rethinking and reinvention of how the web is used, and might be used—circa late-2004.
The phraseology is that of software engineering, where the release of a new version is denoted by appending a number to the software title.
Taken at face-value, the term has proven problematic. Key criticisms of the term are that the web is not a piece of software, and that many of the ideas collected under the Web 2.0 moniker are not ‘new’ in a either a programmatic or technological sense.
Beyond its initial use to describe an approach to software development, the term has also entered popular usage as a synonym for ‘new-ness’—leading to comparisons with pre dot-com bust buzzwords such as ‘killer app’, ‘bleeding/leading edge’, etc.
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