The foundational technology patterns outline the “building blocks” at the heart of any Ajax application. The patterns are considered atomic within the pattern language, in the sense that all later patterns build on these basic techniques. To keep the Ajax Patterns concise, you will only encounter technologies that add something to conventional web development; there’s no “Form Submission” pattern, for instance.
Ajax itself is a pattern, hence the first pattern Ajax App (Chapter 4), which acts as the root for all the Ajax patterns. The next few chapters look at the three core technologies involved in creating an Ajax App. Display Manipulation (Chapter 5) patterns are about repainting the user interface. Web Remoting (Chapter 6) patterns document several alternatives for communicating with the server. The Dynamic Behavior (Chapter 7) patterns are about events—those derived by users and those based on timing. Finally, Extended Technologies (Chapter 8) explains how you can extend an Ajax App with nonstandard technologies.
Not all of these are patterns in a conventional sense—some might argue that a pattern like XMLHttpRequest Call is simply an overview of a technology. Personally, I do see them as patterns insofar as they are good, proven ways to solve recurring problems—it’s just that the problems arise in different contexts and might be applied by different people (such as someone sketching out a potential project or setting up its overall architecture). So while the patterns here do have a different quality, I find the pattern form is a suitable way to document these things, and I find that these foundational technologies—whether you prefer to call them patterns or not—fit nicely into the overall pattern language.