by Yogi

Bootstrap Modal is an excellent way to create a Login form on your website. In this tutorial, you will learn how to create a login feature using Bootstrap for an ASP.NET website. The login Check feature will be created using jQuery AJAX.

I will create the following features Step by Step:

1. A Bootstrap Modal that will contain a login form.

2. The Login Form will contain 2 fields, ‘Username’ & ‘Password’. The user has to enter their values in these fields.

3. On clicking the submit button on the form, the user’s input (username and password) will be sent to the C# function.

4. This C# function will check whether the username and password are correct or not.

5. If they are correct then the user is redirected to the profile page.

You can check out the working DEMO here.

Creating a Bootstrap Modal with a Login Form

Add the reference of “bootstrap CSS, jQuery and bootstrap js” files on the page head.

<link rel="stylesheet" href="">
<script src=""></script>
<script src=""></script>

Next Create a Bootstrap Modal that contains the login form:

<div class="container"><div class="validCredential">
<h3>Try any one of the following three:</h3><div><p>  1. Username: Ram</p><p>  Password: admin</p></div>
<div><p>  2. Username: Shiv</p><p>  Password: admin</p></div>
<div><p>  3. Username: Krishna</p>
<p>  Password: admin</p></div>
<!-- The button that triggers the Modal --><button type="button" class="btn btn-info btn-lg" data-toggle="modal" data-target="#myModal">Open Modal</button>
<!-- Bootstrap Modal --><div id="myModal" class="modal fade" role="dialog">  <div class="modal-dialog">
    <!-- Modal content-->    <div class="modal-content">      <div class="modal-header">        <button type="button" class="close" data-dismiss="modal">×</button>        <h4 class="modal-title">Log in with your Username</h4>      </div>
      <div class="modal-body">        <table>          <tbody>            <tr>              <td>                <input type="text" id="userNameTextBox" placeholder="Username" />              </td>            </tr>            <tr>              <td>                <span id="userNamSpan"></span>              </td>            </tr>            <tr>              <td>                <input type="text" id="passwordTextBox" placeholder="Password" />              </td>            </tr>            <tr>              <td>                <span id="passwordSpan"></span>              </td>            </tr>            <tr>              <td>                <input type="button" id="submitButton" value="Login" />              </td>            </tr>            <tr>              <td>                <span id="messageSpan"></span>              </td>            </tr>            <tr>              <td>                <img id="loadingImg" src="loading.gif" />              </td>            </tr>          </tbody>        </table>      </div>
    <div class="modal-footer">      <button type="button" class="btn btn-default" data-dismiss="modal">Close</button>    </div>  </div><!-- END Modal content--></div>
<!-- END Bootstrap Modal --></div>

This is how the bootstrap modal login form will look.

Bootstrap Modal Login Form

Adding the jQuery Code on the button click event

In the button click, I will force users to enter some value to the username and password fields, before they submit the form.

When both the textboxes contain some value, only then I will be calling the C# function using the jQuery AJAX method. With this method, I will be able to pass the values of the 2 text boxes (username and password) to my C# function.

Add the below jQuery code to your page:

$("#submitButton").click(function (e) {
if ($("#userNameTextBox").val() == "")
$("#userNamSpan").text("Enter Username");
if ($("#passwordTextBox").val() == "")
$("#passwordSpan").text("Enter Password");
if (($("#userNameTextBox").val() != "") && ($("#passwordTextBox").val() != ""))
$.ajax({  type: "POST",  url: "index.aspx/login",  contentType: "application/json; charset=utf-8",  data: '{"username":"' + $("#userNameTextBox").val() + '","password":"' + $("#passwordTextBox").val() + '"}',  dataType: "json",  success: function (result, status, xhr) {    if (result.d == "Success") {      $("#messageSpan").text("Login Successful, Redireting to your profile page.");      setTimeout(function () { window.location = "profile.aspx"; }, 2000);    }    else      $("#messageSpan").text("Login failed, Please try again.");    },   error: function (xhr, status, error) {     $("#dbData").html("Result: " + status + " " + error + " " + xhr.status + " " + xhr.statusText)   }});
$(document).ajaxStart(function () {  $("#loadingImg").show();});
$(document).ajaxStop(function () {  $("#loadingImg").hide();});

In the success callback method, you can see that I am redirecting the user to the profile.aspx page if-and-only-if I receive the “Success” message.

The setTimeout() is a JavaScript function that will redirect to the profile page in 2 seconds.

The following 2 images will explain the login feature:

1. When login fails.
Login Failed for wrong Username and Password
2. When login is successful.
Login Successful when Username and Password are correct

The C# code:

Now in your .aspx.cs page, add the following code:

public static string login(string username, string password)
var cred = LoadCredential();
var count = (from t in cred
where t.username == username && t.password == password
select t).Count();
if (count == 1)
HttpContext.Current.Session["User"] = username;
return "Success";
return "Failed";
class Credential
public string username { get; set; }
public string password { get; set; }
static List<Credential> LoadCredential()
List<Credential> credList = new List<Credential>();
Credential cred = new Credential();
cred.username = "Ram";
cred.password = "admin";
cred = new Credential();
cred.username = "Shiv";
cred.password = "admin";
cred = new Credential();
cred.username = "Krishna";
cred.password = "admin";
return credList;

The login() function is the one that is called by the jQuery method. It checks if the username and passwords are correct and then returns the appropriate message.


To style the login form and the bootstrap modal so that they look perfect, add the following CSS to your page:

.btn {
margin: 15px 0;
#loadingImg {
display: none;
position: absolute;
margin: auto;
top: 0;
left: 0;
right: 0;
bottom: 0;
.validCredential h3 {
float: left;
text-decoration: underline;
.validCredential div {
clear: both;
.validCredential p {
float: left;
padding-right: 10px;
::-webkit-input-placeholder {
color: #ccc;
#myModal {
color: #1fa67b;
#myModal table {
position: relative;
margin: auto;
#myModal table input {
border-radius: 5px;
border: solid 1px #CCC;
margin: 10px;
padding: 3px 10px;
color: #000;
#myModal table input[type="button"] {
width: 94%;
background: #1fa67b;
color: #FFF;
#myModal table span {
float: left;
font-size: 12px;
color: #f00;
padding-left: 23px;

Profile Page

Welcome Message on the Profile Page

On the profile page, the user will get the welcome message. The code of the profile page is the following:

<h1 id="welcomeMessage" runat="server"></h1>
if (!IsPostBack){  welcomeMessage.InnerHtml = "Welcome " + Session["User"] + " to the profile page.";}
Check out the working demo by clicking the below link:

Working DEMO


I hope you liked this tutorial. Feel free to contact me for any questions. I will be there to help if you need it. If you liked this tutorial, then kindly share it on your social accounts.

I have also published another tutorial on freeCodeCamp, you would like to see it too — Master the art of looping in JavaScript with these incredible tricks