[ScriptMethod(ResponseFormat = ResponseFormat.Json)]
[WebMethod]

<script type="text/javascript">
    $(document).ready(function () {
        jQuery.support.cors = true;
        $('#btnAdd').click(function () {
            var a_val = $('#num1').val();
            var b_val = $('#num2').val();
            $.ajax({
                url: 'http://localhost:9001/MyService/MyFunc',
                method: 'posr',
                contentType: 'application/json;charset=utf-8',
                data: JSON.stringify({ a: a_val, b: b_val}),
                dataType: 'json',
                success: function (data) {
                    $('#result').val(data.d);
                },
                error: function (xhr) {
                    alert('Service call failed: ' + xhr.status + ' +' + xhr.statusCode + ' + ' + xhr.statusText + '' + xhr.responseText);
                    alert("Error calling the service.");
                }
            });
        });

    });

</script>