How to programatically reset the session time without page refreshing in ASP.Net

This way

HTML

<asp:ScriptManager ID="ScriptManager1" runat="server" EnablePageMethods="true">
</asp:ScriptManager>
<asp:Button ID="btnReset" Text="Reset" runat="server" OnClientClick="return ResetSession()" />
<br />
Your Session will expire in&nbsp;<span id="seconds"></span>&nbsp;seconds.
<script type="text/javascript">
    var interval;
    function SessionExpireAlert(timeout) {
        clearInterval(interval);
        var seconds = timeout / 1000;
        document.getElementById("seconds").innerHTML = seconds;
        interval = setInterval(function () {
            seconds--;
            document.getElementById("seconds").innerHTML = seconds;
            if (seconds == 0) {
                window.location = "Expired.aspx";
            }
        }, 1000);
    };
    function ResetSession() {
        PageMethods.ResetSession(OnSuccess);
        return false;
    }
    function OnSuccess(response, userContext, methodName) {
        SessionExpireAlert(response);
    }
</script>

Namespaces

using System.Web.Services;
using System.Configuration;
using System.Web.Configuration;

Code

protected void Page_Load(object sender, EventArgs e)
{
    Session["Reset"] = true;
    int timeout = GetSessionTimeout();
    ClientScript.RegisterStartupScript(this.GetType(), "SessionAlert", "SessionExpireAlert(" + timeout + ");", true);
}
[WebMethod(EnableSession = true)]
public static int ResetSession()
{
    HttpContext.Current.Session["Reset"] = true;
    int timeout = GetSessionTimeout();
    return timeout;
}

private static int GetSessionTimeout()
{
    Configuration config = WebConfigurationManager.OpenWebConfiguration("~/Web.Config");
    SessionStateSection section = (SessionStateSection)config.GetSection("system.web/sessionState");
    return Convert.ToInt32(section.Timeout.TotalMinutes * 1000 * 60);
}

Web.Config

<sessionState timeout="1"/>