AJAX Asynchronous JavaScript and XML | Part 2
AJAX – Advantages and Disadvantages
The advantage of this method is primarily the speed at which an AJAX application responds to user actions, which are treated (in part at least) locally by the browser. Respecting largely Web standards (W3C and IETF), AJAX also has qualities of portability. Very quickly deployed, Ajax can reduce development costs for small applications and renewal costs of computer equipment, for AJAX works with relatively low hardware resources including single client does not require lots of memory (as opposed to technology JAVA), just a browser, a simple Web server.
Only condition: choose a standards-compliant browser and also accepting the use of JavaScript (and in particular the XMLHttpRequest object), or alter the code so that Web pages be read by any browser type ( these browsers are becoming more rare) and that users do not want to activate the functionality of JavaScript compatible browser.
Users Ajax applications should in fact allow the execution of JavaScript code via the browser, which can raise fears about security issues (however, there are effective anti-virus blocking scripts). Not using the standard JavaScript XMLHTTP component, versions of Internet Explorer 5 or 6 for Windows must allow ActiveX, unlike other browsers (Firefox, Safari, Opera, etc.), But the IE version 7 is compatible. It is therefore advisable to test Ajax applications on each type of browser, due to non compliance by some Web browsers editors.
Another drawback is the question of referencing as the crawlers are not able to index dynamically generated content.
Finally, several cases of security vulnerabilities such as “code injection” were reported in 2005 and 2006 with AJAX solutions deployed as standard. In this regard, it should be remembered that the majority of the applications deployed as standard are vulnerable.
This recommendation is not specific to AJAX, it is valid for any technology and any development. As with almost any computer application, a security code, server and client is necessary with AJAX. This will result initially in a secure Web server and JavaScript code libraries, and, by client side to update the browser and install antivirus software blocking malicious scripts.
As with any Web development, connection to the secure https protocol is also a solution to secure trade between the client and the server distributing Web pages.
Ajax development environments
To facilitate the use of these technologies, many frameworks have been established. It is usually a set of javascript libraries to achieve the asynchronous treatments and offer advanced ergonomics through a range of graphic objects mature.
For the sake of industrialization, many of these frameworks have been coupled to web development frameworks.
It is estimated that more than 500 the number of existing frameworks Javascript.
The main ones in the article Ajax Frameworks:
Server-side Ajax principle implies that we have the choice of technology. However, some technology-oriented events have a high potential productivity.
- Ruby and especially Ruby on Rails
- . NET 2.0 Microsoft is developing a framework for ASP.Net (Microsoft ASP.Net Ajax).
Morfik WebOS
- AppsBuilder of Morfik is an IDE for AJAX applications complete with a ‘designer’ visual and choice of programming language (Pascal, Basic Java, C #).
- A new approach allows to get rid of JavaScript development, often considered expensive and complex. This approach aims to industrialize the development and symbolized by frameworks like GWT or Echo2.
In parallel developed an ASP.NET Ajax Control Toolkit, which offers numerous controls “ready” for developers using Visual Studio 2005. There are currently thirty controls but Microsoft provides 50-100, all provided with their source. There is also a tutorial on the site for creating your own Toolkit that use Ajax. NET.
In addition, we recently saw the arrival of the design pattern “Comet”, which proposes solutions to make the push data through Ajax.
Open AJAX
IBM has created Open AJAX Initiative, a group promoting the technology with partners such as 24SevenOffice, Adobe Systems, BEA Systems, Borland, the Dojo Foundation, Eclipse Foundation, Google, ILOG, Yahoo, Laszlo Systems, Mozilla Corporation, Novell , Openwave Systems, SAP, Oracle, Red Hat, Tibco, Zend and Zimbra.
The first result of this initiative is the AJAX Toolkit Framework [3] (ATF), a project that aims to provide tools for developing AJAX applications in the Eclipse development tool. This project is based inter-alia on the initial contribution from IBM and various open source AJAX frameworks (such as Dojo and Rico).
Study: From Wikipedia, the free encyclopedia. The text is available under the Creative Commons.
