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So How Do You Code an AJAX Web Page?

Posted by ryuzaki0 on from the hard-work dept.

PetManimal writes "Computerworld has a long excerpt from a book by Edmond Woychowsky about how to code Web pages in AJAX. It gives a good explanation of how the technology works, and also has some visuals and code snippets that you can play with. From the article: 'Beyond the XMLHTTP Request object, which has been around for several years as a solution looking for a problem, there is nothing weird needed. Basically, it is how the individual pieces are put together. When they're put together in one way, it is nothing more than a pile of parts; however, when put together in another way, the monster essentially rises from its slab.'"

1 of 231 comments (clear)

  1. Huh by Bogtha · · Score: 5, Insightful

    Print version here.

    Zero credibility points for trying to put markup in the <title> element and hiding the printable version behind a javascript:void(0) link.

    If you want the technical stuff, skip about a third of the way down. The first third of the article just repeatedly tells you that Ajax is when the page doesn't "blink".

    The code he supplies is crap. For instance:

    <html> <head>

    <title>HTMLfs</title>
    </head>
    <framese t rows="100%,*">
    <frame name="visible_frame" src="visible.htm">
    <frame name="hidden_frame" src="hidden.htm">
    <noframes>Frames are required to use this Web site.</noframes>

    Things wrong with even this tiny snippet of code:

    • Invalid.
    • Frames (at the very least, he should have used iframes).
    • Cheesy "fuck off" error message instead of functional equivalent.

    Skimming the rest of the article, I see the following mistakes:

    • Using DOM methods without testing for their existence.
    • Browser detection (which is stupid and wrong).
    • Obtrusive JavaScript embedded in the page with old-fashioned HTML attributes.
    • Non-degradable JavaScript form submission with <button> instead of <submit>.
    • Confusion over what elements and tags are.
    • Internet Explorer-only code without error checking or a fallback.

    If this is a representative sample of the book it is excerpted from, steer well clear of it. The whole approach is poor.

    The best way of producing compatible, accessible Ajax applications is to start with the bare HTML and make that work. Only then do you add the JavaScript, and you do it by enhancing the page, not replacing it. For instance, don't use <button onclick="...">, use a normal <input type="submit"> and hook into the form's submit event. That way:

    • It works when JavaScript is unavailable.
    • It works when there's a problem in your code.
    • It works when you find you can't do something halfway through processing the event (e.g. you find that ActiveX is switched off in Internet Explorer, making XMLHttpRequest unavailable).
    --
    Bogtha Bogtha Bogtha