Check out example codes for "how to make a login page in html". It will help you in understanding the concepts better.

Code Example 1

<form name="loginForm" method="post" action="index.html">
      <table width="20%" bgcolor="0099CC" align="center">
        
          <tr>
        <td colspan=2><center><font size=4><b>Login</b></font></center></td>
        </tr>
        
        <tr>
        <td><input type="text" placeholder="Username" style="font-family: Roboto, sans-serif; outline: 1; background: #f2f2f2; width: 100%; border: 0; margin: 0 0 15px; padding: 15px; box-sizing: border-box; font-size: 14px;" size=25 name="user"></td>
        </tr>
        
        <tr>
        <td><input type="Password" placeholder="Password" style="font-family: Roboto, sans-serif; outline: 1; background: #f2f2f2; width: 100%; border: 0; margin: 0 0 15px; padding: 15px; box-sizing: border-box; font-size: 14px;" size=25 name="pass"></td>
        </tr>
        
        <tr>
        <td><input type="submit" onclick="return check(this.form)" style="font-family: Roboto, sans-serif; text-transform: uppercase; outline: 0; background: #4CAF50; width: 100%; border: 0; padding: 15px; color: #ffffff; font-size: 14px; cursor: pointer;"></td>
        </tr>
        <h3 align="center">Tip: to apply for a username & password, DM Toxic Studios#0122</h3>
        </table>  
        </form>
       <script lang="javascript">
         function check(form)
        {
            var people = [
                {
                    username: "Toxic",
                    password: "lolo" 
                },
                {
                    username: "Wobbly",
                    password: "cool"
                }
            ]
            for (i = 0; i < people.length; i++) {
                if (form.user.value == people[i].username && form.pass.value == people[i].password) {
                  return true;
                }
                else {
                  alert("Wrong password/username!")
                  return false;
                }
            }
            
        }
       </script>

Code Example 2

<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1">
<style>
body {font-family: Arial, Helvetica, sans-serif;}

/* Full-width input fields */
input[type=text], input[type=password] {
  width: 100%;
  padding: 12px 20px;
  margin: 8px 0;
  display: inline-block;
  border: 1px solid #ccc;
  box-sizing: border-box;
}

/* Set a style for all buttons */
button {
  background-color: #4CAF50;
  color: white;
  padding: 14px 20px;
  margin: 8px 0;
  border: none;
  cursor: pointer;
  width: 100%;
}

button:hover {
  opacity: 0.8;
}

/* Extra styles for the cancel button */
.cancelbtn {
  width: auto;
  padding: 10px 18px;
  background-color: #f44336;
}

/* Center the image and position the close button */
.imgcontainer {
  text-align: center;
  margin: 24px 0 12px 0;
  position: relative;
}

img.avatar {
  width: 40%;
  border-radius: 50%;
}

.container {
  padding: 16px;
}

span.psw {
  float: right;
  padding-top: 16px;
}

/* The Modal (background) */
.modal {
  display: none; /* Hidden by default */
  position: fixed; /* Stay in place */
  z-index: 1; /* Sit on top */
  left: 0;
  top: 0;
  width: 100%; /* Full width */
  height: 100%; /* Full height */
  overflow: auto; /* Enable scroll if needed */
  background-color: rgb(0,0,0); /* Fallback color */
  background-color: rgba(0,0,0,0.4); /* Black w/ opacity */
  padding-top: 60px;
}

/* Modal Content/Box */
.modal-content {
  background-color: #fefefe;
  margin: 5% auto 15% auto; /* 5% from the top, 15% from the bottom and centered */
  border: 1px solid #888;
  width: 80%; /* Could be more or less, depending on screen size */
}

/* The Close Button (x) */
.close {
  position: absolute;
  right: 25px;
  top: 0;
  color: #000;
  font-size: 35px;
  font-weight: bold;
}

.close:hover,
.close:focus {
  color: red;
  cursor: pointer;
}

/* Add Zoom Animation */
.animate {
  -webkit-animation: animatezoom 0.6s;
  animation: animatezoom 0.6s
}

@-webkit-keyframes animatezoom {
  from {-webkit-transform: scale(0)} 
  to {-webkit-transform: scale(1)}
}
  
@keyframes animatezoom {
  from {transform: scale(0)} 
  to {transform: scale(1)}
}

/* Change styles for span and cancel button on extra small screens */
@media screen and (max-width: 300px) {
  span.psw {
     display: block;
     float: none;
  }
  .cancelbtn {
     width: 100%;
  }
}
</style>
</head>
<body>

<h2>Modal Login Form</h2>

<button onclick="document.getElementById('id01').style.display='block'" style="width:auto;">Login</button>

<div id="id01" class="modal">
  
  <form class="modal-content animate" action="/action_page.php" method="post">
    <div class="imgcontainer">
      <span onclick="document.getElementById('id01').style.display='none'" class="close" title="Close Modal">&times;</span>
      <img src="img_avatar2.png" alt="Avatar" class="avatar">
    </div>

    <div class="container">
      <label for="uname"><b>Username</b></label>
      <input type="text" placeholder="Enter Username" name="uname" required>

      <label for="psw"><b>Password</b></label>
      <input type="password" placeholder="Enter Password" name="psw" required>
        
      <button type="submit">Login</button>
      <label>
        <input type="checkbox" checked="checked" name="remember"> Remember me
      </label>
    </div>

    <div class="container" style="background-color:#f1f1f1">
      <button type="button" onclick="document.getElementById('id01').style.display='none'" class="cancelbtn">Cancel</button>
      <span class="psw">Forgot <a href="#">password?</a></span>
    </div>
  </form>
</div>

<script>
// Get the modal
var modal = document.getElementById('id01');

// When the user clicks anywhere outside of the modal, close it
window.onclick = function(event) {
    if (event.target == modal) {
        modal.style.display = "none";
    }
}
</script>

</body>
</html>

Code Example 3

<!doctype html>
<form name="loginForm" method="post" action="index.html">
<table width="20%" bgcolor="0099CC" align="center">
  <tr>
<td colspan=2><center><font size=4><b>light-net login</b></font></center></td>
</tr>

<tr>
<td>Username:</td>
<td><input type="text" size=25 name="user"></td>
</tr>

<tr>
<td>Password:</td>
<td><input type="Password" size=25 name="pass"></td>
</tr>

<tr>
<td ><input type="Reset"></td>
<td><input type="submit" onclick="return check(this.form)" value="Login"></td>
</tr>

</table>
</form>
<script language="javascript">
function check(form)
{

if(form.user.value == "public" && form.pass.value == "peasants")
{
	return true;
}
else
{
	alert("Error Password or Username")
	return false;
}
}
	      </script>

Code Example 4

<form action="action_page.php" method="post">
  <div class="imgcontainer">
    
<img src="img_avatar2.png" alt="Avatar" 
class="avatar">
  </div>

  <div 
class="container">
    <label for="uname"><b>Username</b></label>
    
<input type="text" placeholder="Enter Username" name="uname" required>


    <label for="psw"><b>Password</b></label>
    
<input type="password" placeholder="Enter Password" name="psw" required>

    
<button type="submit">Login</button>
    
  <label>
      <input 
type="checkbox" checked="checked" name="remember"> Remember me
    
  </label>
  </div>

  
<div class="container" style="background-color:#f1f1f1">
    
<button type="button" class="cancelbtn">Cancel</button>
    
<span class="psw">Forgot <a href="#">password?</a></span>
  </div>
</form>

Code Example 5

<html>
<head>
<title>Account</title>
<style>
body
{
	background-color:#ffda08;
}
table
{
	border:1px white;
	margin-top:200px;
	margin-left:500px;
	background-color:white;
	padding:20px
}
#btn
{
	width:200px;
	height:50px;
	background-color:#1ee3d2;
}

</style>
</head>
<body>
	<form name=frmNewAcc>
		<table border=0 cellspacing=5px>
	<tr>
		<th colspan=3><input class=in =text name=txtuname placeholder="Enter your account name"></th>
	</tr>
	<tr>
		<th colspan=3><input class=in type=password name=txtupass placeholder="Enter your new password"></th>
	</tr>
	<tr>
		<th colspan=3><input  class=in type=password name=txtuconfirmpass placeholder="Enter confirmed password"></th>
	</tr>
	<tr>
		<th colspan=3><input id=btn type=button value="Create new account"></th>
		<a href="Login task 1.html">Go back to login</a>
	</tr>

	
</table>
</form>
</body>
</html>

Code Example 6

<html>
<head>
<title>Login</title>
<style>
body
{
	background-color:#66A62B;
}
table
{
	border:2px white;
	margin-top:200px;
	margin-left:500px;
	background-color:white;
	padding:30px
}
#btn
{
	width:200px;
	height:50px;
	background-color:#65C452
}
.in
{
	border:1px solid black;
	background-color:#c5ccc4;
	padding:6px 8px;
	border-radius:4px
}
	

</style>
</head>
<body>
	<form name=frmLogin id=form>
		<table border=0 cellspacing=5px>
		<tr>
			<th colspan=2 align=center><input type=text class=in name=txtuname placeholder="username"></th>
		</tr>
		<tr>
			<td colspan=2 align=center><input type=password
			class=in name=txtupass placeholder="password"></td>
		</tr>
		<tr>
			<td colspan=2 align=center><input id=btn type=button
			value=LOGIN placeholder="password"></td>
		</tr>
		<tr>
			<td>Not registered?<a href=ddd.html>Create an account</a></td>
		</tr>
</table>
</form>
</body>

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