Self host WCF (Windows Communication Foundation) Ajax services

Question

I am having trouble to understand how to expose the WCF services through Javascript. Here are what I found after days of research:

1. Exposing WCF services through Javascript but not self host: http://msdn.microsoft.com/en-us/library/bb472488.aspx In this example, it requires the creation of a .svc file <%@ServiceHost language="c#" Debug="true" Service="Microsoft.Samples.XmlAjaxService.CalculatorService" Factory="System.ServiceModel.Activation.WebServiceHostFactory" %>

2. Self host WCF Ajax services but not exposing the services through Javascript. http://msdn.microsoft.com/en-us/library/bb943471%28v=VS.100%29.aspx

Please help. Thanks.