If you use the ASP.NET AJAX script manager with a service reference to a local WCF service, then you may encounter problems when using HTTPS on the page. If you have not configured your service for use with HTTPS you will most likely receive 'xyzService is not defined' errors in your Javascript. This is because when you add a service reference to '~/Services/xysService.svc' the AJAX Script Manager will import '~/Services/xyzService.svc/js' (or '~/Services/xyzService.svc/jsdebug') to define the prototypes for calling the service. This will return a '404 - Page Not Found' error when using the HTTPS protocol. In order to register the service for use over HTTPS you need to create a configured binding for this:
  <bindings>
     <webHttpBinding>

       <binding name="webHttpsBinding">
         <security mode="Transport"></security>

       </binding>

     </webHttpBinding>

   </bindings>

<services>
    <service name="WebNs.xyzService">
    <endpoint address="" behaviorConfiguration="WebNs.xyzServiceAspNetAjaxBehavior"
     binding="webHttpBinding" bindingConfiguration="webHttpsBinding" contract="WebNs.xyzService" />
   </service>
This configures your service to serve up over HTTPS. Make sure you add the HTTPS binding in IIS for this to work!