Open the DatePicker popup upon focusing input of DatePicker in ASP.NET Core DatePicker control

<ejs-datepicker id="datepicker" focus="onFocus" placeholder="Choose a Date"></ejs-datepicker>

<script>
    function onFocus (args) {
        var datepickerObject = document.getElementById("datepicker").ej2_instances[0];
        datepickerObject.show();
    }
</script>

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;

namespace EJ2CoreSampleBrowser.Controllers
{
    public class HomeController: Controller
    {
        public ActionResult sample()
        {
            ViewBag.value = new DateTime(DateTime.Now.Year,DateTime.Now.Month,14);
            return View();
        }
    }
}