index.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <link rel="stylesheet" href="hi.css">
    <title>Login Page</title>
</head>
<body>
   
    <div class="info">
        <h2 class="login">Login</h2>
    <div class="name" for="name">Username
        <input id="name" placeholder="Enter username " required>
    </div>
    <div class="password" for="pass">
        Password
        <input id="pass" placeholder="Enter password" required >
    </div>
</div>
  <div class="but">
    <button type="button" onclick="enter()">Submit</button>
  </div>
<script>
    
    
        function enter() {
            
            var user=document.getElementById('name').value;
            var pass=document.getElementById('pass').value;
            if(user==="gvpce" &&  pass==="we@12345_"){
                window.location.href= 'data.html';
            }else {
                alert("Invalid Username or Password :( ");
            }
        }
        
            
        
        
    
</script>
    
    
</body>
</html>