How to make login authentication page in HTML or JAVASCRIPT

Question

I am from electronics background so don't have good knowledge in designing webpages. I am doing an ethernet project and for that I need to make a webpage but before that webpage I also need to make a login authentication webpage. I somehow managed to do it using HTML JAVASCRIPT but the problem is anyone can see the username password by viewing the page source.

I am having hard time making authentication. I have basic knowledge of HTML and JAVASCRIPT but ready to learn. All I can find on google is login templates but I don't even know how to use them.

Can anyone give me an example or point me to some good links.

Answer 1

HTML and Javascript are interpreted on the client side. For login purposes, it is the server side code that is commonly used to verify the credentials - simply because that fact that you are already aware of - with a simple client side implementation, you can see the credentials in source code, server side is also easier to work with, once you understand it, it is more flexible for further development, it is more secure, and it is really used everywhere for this task.

It is a good idea to use PHP, ASP, Ruby (or any other server side language) for this. If you do not want that, you need to make it hard for the user to read the credentials from the source code.

In order to do that, you can use various methods like cryptography or obfuscation. Cryptography is highly recommended over obfuscating as it provably adds more security to your application. Obfuscating basically means that you change the source code in a way that it is hard to read - you add functions that encode strings, so that your "password" can not be spotted on the first sight. However, obfuscation can always be bypassed, and usually quite easily with a good debugging tools.

So, let's go with cryptography. What you are looking for here is using one way hash functions. You have plenty to choose from - MD5, SHA1, SHA256, ... each provides different level of security. SHA256 implementation in Javascript is an example you can use. There are many other libraries and examples for this, so just use Google and find the one that you like.

Now, what to do with it? Say you have sha256() function that accepts a string and returns its hash as a string. For each user and password you have, you precount SHA256 hash of string "user + password".

Say, you want your username to be "Pedro" and password for this account is "MyPassword".

You precount the hash of "PedroMyPassword" - e.g. with with online hashing tool. You can see the its SHA256 hash is

40be6e939eedf018b2b846e027067dcb006585a2155ce324f1f2a6a71d418b21

This hash is what you put into your Javascript code.

When the user enters their user and password, you call your sha256 function on "username + password" and you compare it to your precounted hash.

Note that you have to select really strong password, otherwise certain attacks (such as dictionary attack) would be easy to use to break your hash.

The problem is now, that you did not specify, what you want to do next. For example, you might want to redirect authenticated users to next page, but here you have the same problem again - if you have redirection in Javascript to "secondpage.html" in your code, someone could just skip the authentication and navigate to this second page directly.

What you can do in this case is that you name your second page as

40be6e939eedf018b2b846e027067dcb006585a2155ce324f1f2a6a71d418b21.html

i.e. the hash of your user+pass string. In this variant you do not put the hash in the code at all. The web server will just return error 404 for all users that fail to authenticate. For example, if someone attempts to use "Pedro" with "123456" as password, the SHA256 would be

3bac31720fdd4619ebe2e8865ccc0dc87eb744f3f05f08c628bb9217a77e4517

and if you redirect them to

3bac31720fdd4619ebe2e8865ccc0dc87eb744f3f05f08c628bb9217a77e4517.html

it won't exist, because your second page file is called

40be6e939eedf018b2b846e027067dcb006585a2155ce324f1f2a6a71d418b21.html

You would need to create these second pages for each user/pass combination. You could then put a simple redirection code to the real second page.

But make sure you are using HTTPS protocol, otherwise, the second pages would go through the wire unencrypted ...

This all will work, but still, I highly suggest, you consider the server side way.

Answer 2

<html>
<head>

<title>Login paget</title>
</head>
<script type="text/javascript">
function display(form){
if (form.username.value=="root") { 
		if (form.password.value=="root") {              
										location="page2.html" 
											} else {
													alert("Invalid Password")
													}
								} else {  alert("Invalid Username")
										}
						}
			</script>			
<body >

<form >
<input type="text" name="username" /><br><br>
<input type="password" name="password"/><br><br>
<input type="button" value="Login" onClick="display(this.form)"/>

</form>

</body>
</html>

Hello I have created a login page for you using html and Javascript. The Username and password are root. You see if you input correct username and password then the page directs to page2.html and this will show you

This webpage is not found

ERR_FILE_NOT_FOUND

so what you have to do is replace page2.html with your next page name.

Answer 3

You can't really have a secure authentication system using JavaScript and HTML alone.

I would suggest Basic HTTP authentication on your server instead, as it is much more secure (not perfect by any means, but at least employs a standard server-side method of access control).

If you must implement something in JavaScript, you could do a password only scheme based on the name of a hidden directory. Something like the following (note this is untested so will need some tweaks):

(Code borrowed and adapted from this question)

<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js"></script>
<script>
   $(function() {
      var url = "some_url";
      $.ajax(url,
      {
         if (statusCode == 200) {
           document.location.href = url;
         }
         else {
           alert('Incorrect password')
         }
      }
   });   
});
</script>

<input type="password" /><a href="javascript:void(0)">Login</a>

The code should be finished so that the function is called when the button is clicked. So if the password is foo, you set a directory on your website called foo, and if the JQuery JavaScript detects that the entered password matches a directory name (e.g. /foo/), then the user is redirected there. Therefore you'd create a /foo/index.html in order to take care of the user's logged in session.

Note that this is the most secure thing you can do with JavaScript and HTML alone and it suffers from the following vulnerabilities.

• It requires that the URL be kept secret, although this can be leaked by the referer header, by browser history and server/proxy logs.
• Once a user is logged in, they are always logged in (they could bookmark the logged in pages)
• There is no easy way to revoke a password.
• There is only one password.
• Anyone with access to view files on the server could view the directory structure and learn the password.
• The URL may be leaked by analytics tools.
• Assumes directory browsing on your server is disabled (or that there's a default page in the private page's parent directory).

In any case, always protect your server with TLS/SSL. My recommendation is to properly create a user authentication system using the advice from OWASP. The above shows only what's achievable in basic HTML (not much). However, it is better than exposing the password within client-side files.