Error in calling windows authenticated WCF service from JavaScript web resource

Hello,

I have a JS webresource and a WCF service. WCF service is hosted on same server as MS Dynamics CRM. 

Authentication mode for WCF service is set to windows. 

When I call service from JS, it gives '401 unauthorized' error. I have tried all possible ways found over net, still no luck.

Service call is something like this,

 $.ajax({
            async: true,
            type: "POST",
            contentType: "application/json; charset=utf-8",
            data: '<DATA>',
            url: <service url>
            success: function (data) {
                OnFetchSuccess();
            },
            error: function () { }
        });

The idea is that the service call should be made from user who has logged in to the CRM application.

Can someone provide pointers for the same?

Regards,

Vijay