Authentication of login using javascript in asp.net

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C#

ASP.NET

Javascript

Hello everyone,

I want to authenticate my login page using javascript in asp.net .

if the user is authenticated then it should redirect to home page else it should say invalid login.

I have managed something like this but it is not working as desired.

my login control..

<table style="font-size: 20px;" >

                  <tr>
                        <td>
                            Username
                        </td>
                        <td></td>
                        <td>
                            <%--<input type="text" runat="server" id="username" name="username"  style="height :20px; width :200px;"  />--%>
                            <asp:TextBox ID ="txtUsername" runat ="server" style="height :20px; width :130px;"  ></asp:TextBox>
                        </td>
                  </tr>
                    <tr>
                        <td></td>
                    </tr>
                    <tr>
                        <td>
                            Password
                        </td>
                        <td></td>
                        <td>
                            <%--<input type="password"  runat="server" id="password" name="password" style="height :20px; width :200px;"/>--%>
                            <asp:TextBox ID ="txtPassword" runat ="server" style="height :20px; width :130px;" textmode="Password"></asp:TextBox>
                        </td>
                    </tr>
                    <tr>
                        <td></td>
                    </tr>
                    <tr>
                        <td>
                            <span id="resultspan"></span>
                        </td>
                        <td></td>
                        <td>
                           <input type="button" name="submit" id="submit" value="Submit" onclick="checkLoginDetails();"/>
                        </td>
                    </tr>
             </table>

<script type="text/javascript">

     var xmlhttp;
     function loadXMLDoc(url, cfunc) {
         if (window.XMLHttpRequest) {// code for IE7+, Firefox, Chrome, Opera, Safari
             xmlhttp = new XMLHttpRequest();
         }
         else {// code for IE6, IE5
             xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
         }
         if (xmlhttp != null) {
             xmlhttp.onreadystatechange = cfunc;
             xmlhttp.open("GET", url, true);
             xmlhttp.send();
         }
         else {
             alert("Page can not process");
         }
     }


     function checkLoginDetails() {
         // var username = $('#username').val();
         // var password = $('#password').val();
         var username = document.getElementById('<%= txtUsername.ClientID %>').value;
         var password = document.getElementById('<%= txtPassword.ClientID %>').value;
         var url = "";
         if ((username == null || username == '') && (password == null || password == '')) {
             alert("Please enter Username and Password.");
             return;
         } else if (username == null || username == '') {
             alert("Please enter Username.");
             return;
         } else if (password == null || password == '') {
             alert("Please enter Password.");
             return;
         }
         url = "AjaxFunctions.aspx?username=" + username + "&password=" + password + "&Action=login";
         loadXMLDoc(url, function () {
             if (xmlhttp.readyState == 4 && xmlhttp.status == 200) {
                 
                
                     alert('Hi');
                     //document.getElementById("myDiv1").innerHTML = xmlhttp.responseText;
                     window.location = '<%= ResolveUrl("~/Home.aspx") %>';
                
                 
             }
             else {
                 alert('Invalid login');
             }
         });
     }
    </script>

my ajax function...

 private void Login()
    {
        try {

            sq = new SQLDataAccessHelper();
            string userName = Request.QueryString["username"];
            string password = Request.QueryString["password"];
            DataSet ds = new DataSet();
            SqlParameter[] param = new SqlParameter[2];
            param[0] = new SqlParameter("@username", SqlDbType.NVarChar);
            param[0].Value = userName;
            param[1] = new SqlParameter("@password", SqlDbType.NVarChar);
            param[1].Value = password;
            ds = sq.ExecuteDataSet("usp_authenticate_user", param);
            if ((ds.Tables[0].Rows.Count != 0) && (ds.Tables.Count != 0) && (ds != null) && (ds.Tables[0].Rows[0]["Message"].ToString().ToLower() == "y"))
            {
                Session["Username"] = userName;
                
                //Response.Write(strXmlval);
                 //Response.Redirect("Home.aspx", false);
            }
            else if ((ds.Tables[0].Rows.Count != 0) && (ds.Tables.Count != 0) && (ds != null) && (ds.Tables[0].Rows[0]["Message"].ToString().ToLower() == "n"))
            {
               // string strXmlval = "<responseText>" + 0 + "</responseText>";
               // Response.Write(strXmlval);
            }

        }
        catch (Exception ex) { throw ex; }
        finally { }
            
                  
        
    }

now what happens is........with correct userid and password it goes to home page...but for wrong userid and password also it goes to home page...

and when i debugged javascript using alerts it gave me four times the alert box as 'Hi'

please help me how to make this thing possible...

regards,
krunal panchal