Start Clean
Adding Ajax to your site is an opportunity to do that page cleanup you've probably been wanting to do for a long time, but couldn't find the time. Dynamic effects and the use of old and outdated HTML don't go together well, particularly if you're moving objects around, collapsing and expanding columns, or doing in-place editing or help.
In a weblog post at O'Reilly Radar, Nat Torkington wrote the following account of Mark Lucovsky's attempt to implement the same bit of Ajax functionality into two very different web sites; one clean and the other with a large amount of "baggage" (http://radar.oreilly.com/archives/2006/08/the_value_of_web_standards.html:
While at OSCON, Mark Lucovsky of Google sent us a bit of HTML that'd embed a slender map search widget into our conferences web site. It's an easy way for attendees to find restaurants, hotels, parks, bars, etc. near the conference venue. Great idea, and an elegant demo of the Ajax Search API that Mark's been working on.
Mark's next speaking gig was at the Search Engine Strategies (SES) conference, so naturally he reached for the find-me-stuff-around-the-conference example. However, he rapidly ran into the messy HTML that is the SES web site. Whereas it had been a matter of seconds to add the JavaScript into the O'Reilly web page, adding it to the SES page was an ordeal.
That's a vindication of the large amount of hard work that [the] O'Reilly design team put into redesigning pages so they were XHTML and CSS. It's also a vindication ...