AJAX Buzzword Reinvigorates Javascript

samuel4242 writes "Javascript may have been with us since the beginning of the browser, but it's going through a renaissance as companies like Google create Javascript-enabled tools like Google Maps . There's even a nice, newly coined acronym , AJAX for "Asynchronous Javascript and XML". A nice survey article from Infoworld interviews Javascript creator, Brendan Eich, who says that this is what he and Marc Andreessen planned from the beginning. Perhaps AJAX will finally deliver what Java promised. Perhaps it will really provide a solid way to distribute software seamlessly."

Comments

AJAX also good for...

[Anonymous Coward]

cleaning tub
cleaning toilet
getting first post

Re:AJAX also good for...

[nahdude812]

Oh, and getting all the Slashdot pundits on their soap boxes, preaching about technologies they don't really understand, and making dire predictions about the unworthiness of the tech.

Seriously, being someone who actually has quite a bit of *real* experience with Ajax (though we were doing it before the term was coined) across multiple browsers, I can say that the ratio of comments which demonstrate the author understands the full implications of Ajax to those who are just spouting nonsense is about 1:75. I've never read an article on Slashdot before where so many comments missed the target, and I feel like I've been around Slashdot for a little while.

The idea behind Ajax *does* revolutionize the web paradigm. All this nonsense about cross browser compatability issues is just that: nonsense; it works in Mozilla, Firefox, IE, Opera, and Konqueror each on their respective available platforms. I've actually heard people talking about "Ajax enabled advertisements instead of Flash." Other gems like "Ajax doesn't do anything that a well programmed web application can't do," and "It's just needlessly complex web pages" only point to users who fail to grasp the fundamental concept.

Let me tell you: Ajax is FAST. You don't realize how unresponsive web pages are until you get to play with a web app that is always waiting on you, no the other way around. When I submit information, why do I need to wait for that information to get to the server before I can begin to perform another operation if that operation isn't dependant on the previous? Click Add To Cart then *immediately* start searching for the next item. Stuff like that.

The amount of data being exchanged is far less (if you do it RIGHT, you people who are talking about using the XMLHttpRequest.responseText property, this does NOT include you). Rather than reload an entire page with all the framework, you're loading only the portion of the page that changed.

Aside from piecemeal page loading, you also get to load only the relevant data. For example, rather than load a form, and all the form formatting to make the text fields line up correctly, and all the validation code to validate that form, you load a series of XML tags that contain only the basic information needed to tell the client how to lay out the form. The client takes care of generating the HTML for the form, and your form data looks more like this:
<input name="username" label="User Name" required="yes" minlength="5" maxlength="10"/>
versus
<tr class="lightRow"><td class="labelColumn"><label for="username">User Name:</label></td><td class="inputColumn"><input id="username" name="username" maxlength="10"></td></tr>
, then later form validation code.

Often times your data fits inside a single TCP packet.

I'll make this concession: yes, this is stuff that could be done before the Ajax philosophy using Flash or Java Applets. But both require a plugin, and one of them is even proprietary. Both have potential firewall issues, and neither will run on a vanilla Fedora Core build. Both require higher resource consumption for the user, and both lend to a feeling of sluggishness on the site for the user.

That's not to say that it's not without its dangers. Like all web apps, you can't trust the data from the client. Here the client gets a bit lower level access to the data. You still have to make sure that you're protecting yourself well against data poisoning attacks.

The thing I like most about this model though is this: It's truly a MVC (Model View Controller) framework.

The model is of course your server side logic scripts. The View is the browser (the server side logic scripts send back generically formatted data, the browser does all the display). The Controller is the combination of XMLHttpRequest object, and the processing management script on the server. It's very conceivable that you could write a new front end for your application by simply

Rewriting history?

[Anonymous Coward]

Javascript may have been with us since the beginning of the browser...

Huh? I don't seem to remember seeing it until about '96 or '97. That's just a wee bit later than the beginning of the browser...

this is good, and here's more material

[yagu]

For me, the crux of the usefulness and eventual adoption and finally complete embracing of AJAX lies in the article's paragraph:

Some of the buzz surrounding AJAX has been generated by Web designers as well as programmers. AJAX?s flexibility is invigorating for Web designers because JavaScript can control any aspect of any images or type on a page. Fonts can grow or shrink. Tables can add or lose lines. Colors can change. Although none of these capabilities are new to programmers accustomed to building client applications -- or, for that matter, Java applets -- they are novelties to Web designers who would otherwise be forced to rely on Macromedia (Profile, Products, Articles) Flash.

I've seen what Google has done with AJAX (e.g., Google suggest), and it's stuff I never imagined could be so repsonsive in a web context. For me it starts to make programming fun again, and web programming an acceptable form of application development.

When browsers and web first emerged I could see the writing on the wall, but I wasn't happy about it. Browser application writing from the programming perspective was probably the single most giant leap backwards in technology for me (not including technologies introduced by Microsoft)....: you mean, all the years I've spent honing skills writing applications no longer apply? You mean I no longer have "state" as a tool for maintaining sanity in my application???? Hwaahhh??? I have to do what to change the web page???

While there have been some technologies (ASP, JSP, etc) to help with these issues, none have addressed the responsiveness issue with the web page round trip message loop. AJAX comes close. Now all I have to do is learn it.

For a great example of the responsive nature of this (I've referenced this before), go to Google Personal Home, set up your own home page, and play... Configure your modules by dragging them around... open and close your g-mail previews. This all starts looking alot like programs actually running locally on your own machine. (I'm assuming all are familiar with and have played similarly with Google Maps.)

Additionally, here are some very good resources to learn more about AJAX:

• Very Dynamic Web Interfaces
• XMLHttpRequest Introduction
• An example
• Using the XML HTTP Request object
• Dynamic HTML and XML
• XMLHttpRequest API madness
• Sarissa
• JavaScript: The World's Most Misunderstood Programming Language
• What kind of language is XSLT?

That's it, I'm done.

Open up AJAX

[iamthesamurai]

There is a need to standardize (as much as possible) the way that AJAX will work in the browser. There are a lot of code-writers and code-copy-n-pasters out there. When you visit one of these sites, you know because the browser may act funny due to poor programming/hacking of Javascript interacting with the server. AJAX is much bigger than just XML messaging, it's an opportunity to bring a more traditional application model to the browser via Event handling and dispatching. Notice that if you have an engine or framework that is well built, it's quite simple to add event handlers like key presses or mouse clicks or even drag-n-drop. If one was to script each element on a page, that gets heavy and can slow the browser. Which - btw, is why AJAX hadn't caught on until recently: computing resources were not sufficient in many cases.

That being said, everyone should look at http://www.sourcelabs.com/ajb/AJAX Mistakes. There's also a nice list being compiled at http://www.openajax.net/OpenAJAX .net. This combination of technologies has been around for a while, however, as people find them more useful and interesting, there is a need for good information and a solid foundation for folks to work off of.

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Re:Javascript?

[telbij]

Quite honestly javascript is a very poor language.

Actually, Javascript is surprisingly robust. Probably you're referring the platform inconsistencies, which have long been a showstopper. But with recent versions of browsers supporting the javascript standard (ie. ECMAScript) increasingly well, a lot of the major wholes are closing, and you really can write cross-platform javascript with a minimal compatibility layer.

Javascript is not meant to be a large-scale programming language... it doesn't have strong-typing or other features that you want when developing million-line applications. However, it is still an extremely powerful language providing things like full object-orientation (everything is secretly descended from the window object), comprehensive hooks to HTML, functions as data, regular expressions, flexible data access (eg. objects as hashes), and robust event handling.

I used to think of javascript as a toy language, but when you get to down to it, it does what it needs to do very cleanly and efficiently without imposing unnecessary overhead on the programmer.