This was easily the best talk of the day in both content and presentation (no bullet points, no reading from the screen, very few slides, great metaphors). Jon started with explaining that everyone likes speed. This is one area where designers and developers see eye to eye. He argued that there were two ways to enhance performance of an app - efficient code and using available system resources. He then explained the concept of pre-fetching data with valet parking metaphor (this part of the talk can be seen in this video clip
). Ajax works like magic, he argued, because while your attention is focused on one task, something else is happening at another place - the classic principle of misdirection in magic.
The basic idea of Jon's talk was that the secret of a fast Ajax app lies in deciding what to pre-fetch. You take the decision by doing user research - building a model of how the app will be used, conducting user testing and by identifying the value and cost of pre-fetching different kinds of data. The value must always override the cost.
All of Jon's blog posts on Ajax
, Jon's company - UzantoAll my posts reviewing BarCampDelhi