From XML to Ajax for dummies
Everyone working close to high tech hears the word “XML” at least thrice a day. Back in 2001 when XML was in the process of democratizing, everyone became crazy about it. Some venture capitalists exclusively wanted to invest in start ups that “used XML” – hence the famous dummy investor question: “does your product use XML?” (see an occurrence here in a Paul Graham essay). I was sort of taking part of a conversation this week that included at some point a question very similar to what used to happen with XML: “do you have Ajax on your website?”. I immediately thought I would very quickly draw a very simple historical vision linking these 2 technologies to lower the risk of hearing such things again (focus on the use, not the technology).
XML (Extensible Markup Language) introduced a major change vs. put-and-get-between-client-and-web server HTML.
XML allows for tearing apart data & the actual layout. Structured content ease applications when communicating together, without having humans interact in this whole process. On top of being conceptually interesting, XML making a difference between content & form help limit the load of data circulating on the network. Consequently, it is now possible to access the same data from different terminal devices (PCs, TVs, PDAs, mobile phones, pagers, watches, showers, etc.). Sending data through XML messages is called “parsing”.
Although I’m not going to give any better explanation on XML than Wikipedia, O’Reilly and W3, I see 2 reasons why XML is a long term thing on the Web:
- XML is both readable by a human and a machine;
- XML is text, the most widespread standard in the world (no proprietary format).
XML helped give birth to Ajax, an asynchronous combination of script language Javascript & XML.
Ajax basically allows, through on-the-fly data parsing, for refreshing part of a web page. Thanks to Ajax, you don’t need to reload the page and send the same requests all over again everytime you breathe. In other words, Ajax saves bandwidth – hence the device portability potential of such a technology (ex. Google Reader on a Smartphone).
Ajax is one of the technologies behind the web app takeoff: a good Ajax programmer can now build applications that compete in performance against fat-client, more traditional software.
LikeRelated posts:
.NET (C#), Amazon, CIO, Consulting, Education, Europe, Finance, Friends, Google, Internet, Java, Microsoft, Software, Venture Capital, eBay, open-source
Thank you Jeremy, It was actually the point of the last email I sent you. But I still don’t understand why you adviced me to start learning an object oriented language like Java before XML.
Because one can’t really “learn” XML. It’s good to know what it’s all about, but you’re going to have to play with it anyways.
Conversely, the ability to model specifications and to write nice, readable, maintainable object oriented code, I believe, is the basics. And I can tell you it takes time and is far from easy (I’m still learning and far from being fluent in object modeling), but at the end of the day, you can’t do anything in programming if you can’t develop using the object oriented philosophy.