Full Service: The Yahoo Developer Network and User Interface Library Yahoo, being one of the oldest Internet content and service providers, has taken an interesting step by offering the Yahoo Developer Network to web developers. The network homepage is http://developer.yahoo.com, and there you can find a listing of all Yahoo APIs, RSS feeds, and REST services. The really interesting approach is that the REST results are also available in JSON format in many cases, which means that you can embed them as data in a SCRIPT element without having to use Ajax at all. There is also a JavaScript developer center at http://developer.yahoo.com/javascript/, which lists services, articles, and code examples on how to use what Yahoo and its companies can offer you. The Developer Network also includes design patterns, which supply information on how to approach a certain web design task and solutions for it, and a library to develop JavaScript-enhanced web sites and applications from the ground up—including premade CSS for differ-ent layouts and font-sizing issues. This library is called the Yahoo User Interface Library, or YUI for short, and you can download it at http://developer.yahoo.com/yui/. In the download zip file, you can find the library files in the build folder, the documentation in the docs folder, and examples in the examples folder. The library consists of several components that each have to be included as their own tags. The components are available either as readable Java-Script files, for example yahoo.js, or as file-size-optimized versions with file names ending in -min, for example, yahoo-min.js. The latter have no whitespace and are compacted to result in much smaller files.