var height=$(window).height();
			var width=$(window).width();
			//alert(height);
			$.ajax({
			    url: "/getwindowsize.ashx",
			    type: "POST",
			    data : { Height: height, 
			        Width:width, 
			        selectedValue:selectedValue },
			    contentType: "application/json; charset=utf-8",
			    dataType: "json",
			    success: function (response) { 
			        // do stuff
			    }

          
			});

<%@ WebHandler Language="C#" Class="getwindowsize" %>

using System;
using System.Web;

public class getwindowsize : IHttpHandler {
    
    public void ProcessRequest (HttpContext context) {
        //context.Response.ContentType = "text/plain";
        //context.Response.Write("Hello World");
        context.Response.ContentType = "application/json";
        string Height = context.Request.QueryString["Height"];
        string Width = context.Request.QueryString["Width"];
        context.Session["DWH"] = Width.ToString() + "x" + Height.ToString(); 
    }
 
    public bool IsReusable {
        get {
            return false;
        }
    }

}

 context.Session["DWH"] = Width.ToString() + "x" + Height.ToString(); 

public class getwindowsize : IHttpHandler, IRequiresSessionState
...

if (HttpContext.Current.Session["DWH"] != null)
        {
            Literal_Test.Text = HttpContext.Current.Session["DWH"].ToString();
        }

var height=$(window).height();
			var width=$(window).width();
			//alert(height);
			$.ajax({
			    url: "/getwindowsize.ashx",
			    type: "POST",
			    data : { Height: height, 
			        Width:width, 
			        selectedValue:selectedValue },
			    contentType: "application/json; charset=utf-8",
			    dataType: "json",
			    success: function (response) { 
			        // do stuff
			    }

          
			});