I have today launched the first article in my eight part series about the Prototype JavaScript framework.
There will be a new article released each week for the next seven weeks, covering a wide range of topics, such as creating classes and event handling with Prototype.
While the content of these articles is not strictly related to PHP, hopefully as PHP developers you will find them useful anyway in building your own modern day web applications. The final article in this series will cover an extensive example of using Prototype, in which PHP will be used on the server-side.
In addition to being able to read each article for free online, you can purchase a PDF copy of each article for a nominal fee ($5), or purchase the entire 8-part series for $12. If you purchase the entire series you will be notified when each subsequent article is released, allowing you to then download it.