using (Ajax.BeginForm("getCountTasks", "TaskController",
    new AjaxOptions { UpdateTargetId = "countTabledata", Url = Url.Action("getCountTasks") }, new {id = "form" }))
{
    <div id="countTabledata">
        @Html.Action("getCountTasks")
    </div>
   
    <script type="text/javascript">
    var form = document.getElementById("form");
    setTimeout("form.submit()", 5000);
    </script>

<script type="text/javascript">
    function refresh() {
        $('#countTabledata').load('@Html.Action("getCountTasks", "Task")');
    }

    setInterval(refresh, 5000);
</script>

<script type="text/javascript">
    function refresh() {
        $('#countTabledata').load('@Html.Action("getCountTasks", "Task")');
        setTimeout(refresh, 5000);
    }

    refresh();
</script>