In the third installment of the WSwI screecasts author produces a whopping 45 minute episode which will teach you a good approach to developing JavaScript A.P.I.’s using Object Oriented methodologies as well as an all around practical usage of Yahoo! User Interface utilities; most notably the Connection Manager and Custom Event.

For this particular screencast author decided to publish the the code in its fullness so that you may play around with it yourself to get a better understanding of it all. See Yahoo Services Demo. One exception you might notice in the demo code (that is different from the screencast) is that author added one extra bit to prove a point of having an onWebServiceSucess.

You’ll see the beauty in the fact that YAHOO.elseWhere didn’t have to know what anyone else was doing with the web service - and all he/she needs to do is set up the Base WebService object and subscribe to the onWebServiceSucess method.