Using Web Service From Client- Side Code

Before you begin with the client-side code, you should have a server code that will respond to all the requests coming from your client-server code. In this case, I've created a web service to handle the requests. Notice the green comments.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Script.Serialization;
using System.Web.Script.Services;
using System.Web.Services;
using System.Xml.Linq;

namespace DataReaderService
{
    /// <summary>
    /// Summary description for EmpReader
    /// </summary>
    [WebService]
    //[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
    [System.ComponentModel.ToolboxItem(false)]
    // To allow this Web Service to be called from script, using ASP.NET AJAX, uncomment the following line.
    [System.Web.Script.Services.ScriptService]
    public class EmpReader : System.Web.Services.WebService
    {
        [WebMethod]
        [ScriptMethod(ResponseFormat = ResponseFormat.Json) ] //format the returned string value as JSON string
        public string getEmpData(string id)
        {
            //Create a list of 'employee' object
            List<employee> emps = new List<employee>();

            //Load the XML document
            var employee = XElement.Load( Server.MapPath("Employees.xml") );

            //Select the employee with given ID
            var emp = from q in employee.Elements("Employee")
                      where q.Element("EmpId").Value == id
                      select q;

            //Return a message to the client if no data returned
            if (emp.Count()==0) { return "no data";  }

            //Iterate through emp collection to populate a list of 'employee'
            foreach (var element in emp)
            {
                //Gets Phone elements
                var e = from j in element.Elements("Phone")
                        select j;

                object[] phones = e.ToArray(); //Convert phone to array in order to be able to read their values only

                emps.Add(new employee { Name = element.Element("Name").Value, gender = element.Element("Sex").Value, Address = element.Element("Address").Value, HomePhone = ((XElement)phones[0]).Value , WorkPhone=((XElement)phones[1]).Value });
            }

            //return emps;
            return new JavaScriptSerializer().Serialize(emps); //use this to return as JSON object
        }
    }

    public class employee
    {
        public string Name { get; set; }
        public string gender { get; set; }
        public string HomePhone { get; set; }
        public string WorkPhone { get; set; }
        public string Address { get; set; }
    }
}

You may change how the server handles the requests to add more functionality. Now it's time to write our client-side code, and here are some different ways:

Classic JavaScript

var xhttp = new XMLHttpRequest();
        xhttp.onreadystatechange = function () {
            if (xhttp.readyState == 4 && xhttp.status == 200) {
                var server_data = xhttp.responseXML;

                //When using xhttp.responseXML, data can be returned in XML format , we get 'string' TAG contents
                var XMLData = server_data.getElementsByTagName("string")[0].childNodes[0].nodeValue;

        //        //Check if data found
                if (XMLData != "no data") {
                    $("#txtResult").val(XMLData);

                   //parse JSON data
                    var Result = JSON.parse(XMLData);

                    //Draw Header
                   $("#table_results").append("<tr><th>Name</th><th>Gender</th><th>Address</th><th>Home Phone</th><th>Work Phone</th></tr>");

                    //Display data
                   $("#txtResult").val(Result[0].Name);
                   $("#table_results").append("<tr><td>" + Result[0].Name + "</td><td>" + Result[0].gender + "</td><td>" + Result[0].Address + "</td><td>" + Result[0].HomePhone + "</td><td>" + Result[0].WorkPhone + "</td></tr>");


                } else { $("#txtResult").val("No Data found"); }
            }
        };
        xhttp.open("POST", "http://localhost:56998/EmpReader.asmx/getEmpData", true);
        xhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
        xhttp.send("id=" + $("#txtEmpId").val() );

Using $.post method

$.post("http://localhost:56998/EmpReader.asmx/getEmpData",
            { id: $("#txtEmpId").val() },
            function (data) {
                //Get data received from the server in XML format
                var data_packet = data.getElementsByTagName("string")[0].childNodes[0].nodeValue;

                //if invalid number sent, type an error message
                if (data_packet == "no data") $("#txtResult").val("No Data Found");
                else //if data found , draw the table
                {
                    //parse JSON data
                    var json_data = JSON.parse(data_packet);

                    $("#txtResult").val(json_data[0].Name);

                    //Draw the table
                    //1. Draw the header
                    $("#table_results").append("<tr><th>Name</th><th>Gender</th><th>Address</th><th>Home Phone</th><th>Work Phone</th></tr>");

                    //Draw table body and write data
                    $("#table_results").append("<tr><td>" + json_data[0].Name + "</td><td>" + json_data[0].gender + "</td><td>" + json_data[0].Address + "</td><td>" + json_data[0].HomePhone + "</td><td>" + json_data[0].WorkPhone + "</td></tr>");
                }

            });

Using $.ajax method 

$.ajax({
            type: "POST",
            contentType: "application/json; charset=utf-8",
            url: "http://localhost:56998/EmpReader.asmx/getEmpData",
            data: '{id:"' + $("#txtEmpId").val() + '"}',
            dataType: "json",
            success: function (data) {

                //Check if there is data returned from the server
                if (data.d != "no data") {

                    //return all data from the server
                    var Result = JSON.parse(data.d);

                    //Draw Header
                    $("#table_results").append("<tr><th>Name</th><th>Gender</th><th>Address</th><th>Home Phone</th><th>Work Phone</th></tr>");

                    $("#txtResult").val(Result[0].Name);
                    $("#table_results").append("<tr><td>" + Result[0].Name + "</td><td>" + Result[0].gender + "</td><td>" + Result[0].Address + "</td><td>" + Result[0].HomePhone + "</td><td>" + Result[0].WorkPhone + "</td></tr>");
                } else { $("#txtResult").val("No data found"); } //return error message
            },
            error: function (result) {
                alert("Error reading data");
            }
        });

Using AngularJS 

var app = angular.module("NGMainApp", []);


app.controller("MainController", function ($scope, $http) {



    $scope.LoadEmpData = function (variable) {
        document.getElementById("span1").innerText = variable;

        //*******
        var sentPacket = {
            method: 'POST',
            url: 'http://localhost:56998/EmpReader.asmx/getEmpData',
            headers: {
                'Content-Type': 'application/json'
            },
            data: { "id": $scope.NGEmpID }
        }
        //*********
        $http(sentPacket).then(function (response) {

            //alert(response.data.d);
            if (response.data.d != "no data") {
                $scope.IsVisible = true;
                $scope.contents = JSON.parse(response.data.d);
            } else { $scope.IsVisible = false; }

        });
    }

});

Notice: In methods 1 and 2, we get the response from the server as XML node and parse it as JSON data.

Due to the size limit, I uploaded the project here. 

 

Decryption code: !1GKQNhG3V4OT3EstM14ayPYd6-j4VOz7ry_c_UKUpIw