Calling MVC controller from Javascript ajax
<head runat="server">
    <title>FirstAjax</title>
    <script src="http://code.jquery.com/jquery-1.9.1.js"></script>
    <script src="http://ajax.googleapis.com/ajax/libs/jquery/2.0.0/jquery.min.js"></script>
    <script type="text/javascript">
        $(document).ready(function () {
            var serviceURL = '/AjaxTest/FirstAjax';
            $.ajax({
                type: "POST",
                url: serviceURL,
                data: param = "",
                contentType: "application/json; charset=utf-8",
                dataType: "json",
                success: successFunc,
                error: errorFunc
            });
            function successFunc(data, status) {     
                alert(data);
            }
            function errorFunc() {
                alert('error');
            }
        });
    </script>
</head>