In this chapter you learned about application services using Sys.Services and the ASP.NET AJAX server-side implementation. You saw how ASP.NET AJAX uses script initialization to set initial JavaScript values on the server’s page load method, and you learned how to inject your own initialization scripts. Finally, you learned how to use the WCF application services defined in System.Web.ApplicationServices to integrate services that support both local AJAX clients (through AJAX-enabled services) and remote SOAP-based clients. By now, you should be able to integrate application services into your AJAX application for authentication and roles. You should also be able to use the profile service to save and load user preferences during the execution of the application. In the next chapter we’ll look at client-side programming with components, behaviors, and controls in the AJAX library.