http://www.sansys.net/2014/07/wcf-enablewebscript.html

<system.serviceModel>
  <behaviors>
    <endpointBehaviors>
      <behavior name="NewBehavior0">
        <enableWebScript />
        <webHttp automaticFormatSelectionEnabled="true" faultExceptionEnabled="true" defaultBodyStyle="Wrapped" defaultOutgoingResponseFormat="Json" />
      </behavior>
    </endpointBehaviors>
    <serviceBehaviors>
      <behavior name="">
        <serviceMetadata httpGetEnabled="true" httpsGetEnabled="true" />
        <serviceDebug includeExceptionDetailInFaults="true" />
      </behavior>
    </serviceBehaviors>
  </behaviors>
  <protocolMapping>
      <add binding="basicHttpsBinding" scheme="https" />
  </protocolMapping>
  <serviceHostingEnvironment aspNetCompatibilityEnabled="false" multipleSiteBindingsEnabled="true" />

  <services>
    <service name="WcfAndJS.Service1">
      <endpoint address="" binding="webHttpBinding" contract="WcfAndJS.IService1" behaviorConfiguration="NewBehavior0">
      </endpoint>
    </service>
  </services>
</system.serviceModel>