How to call the webmethod on button clickevent for firebase

Hello members,

Hope you are doing good!!

Here i am trying to send the push notification using webmethod.

But it is not hitting on clickevent can anyone guide me.

ASPX:

CS code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Services;
using System.Web.UI;
using System.Web.UI.WebControls;
using RestSharp;
namespace pushnotification
{
public partial class notification : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
[WebMethod]
public void notification_push(string cToken )
{
var client = new RestClient("https://fcm.googleapis.com/fcm/send");
client.Timeout = -1;
var request = new RestRequest(Method.POST);
request.AddHeader("Content-Type", "application/json");
request.AddHeader("Authorization", "key=server key");
request.AddHeader("Content-Type", "text/plain");
request.AddParameter("application/json,text/plain",
"{\n \"to\": \"****************\",\n \"priority\": \"high\",\n \"content_available\": true,\n \"notification\": {\n \"body\": \"Notify talpal\",\n \"title\": \"Talpal\",\n \"sound\": \"sound.caf\"\n }\n}", ParameterType.RequestBody);
IRestResponse response = client.Execute(request);
//Console.WriteLine(response.Content);
}
}
}

Can any one guide me, Thank you in advance!!