function getContact(id, callback) {
    $.ajax({
        type: "GET",
        contentType: "application/json; charset=utf-8",
        datatype: "json",
        url: Xrm.Page.context.getClientUrl() + "/XRMServices/2011/OrganizationData.svc/ContactSet(guid'" + contactId + "')",
        beforeSend: function (XMLHttpRequest) { XMLHttpRequest.setRequestHeader("Accept", "application/json"); },
        async: true,
        success: function (data, textStatus, xhr) {
            callback(data.d);
        },
        error: function (xhr, textStatus, errorThrown) {
            console.error(errorThrown);
        }
    });
}