HTML Code

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <title>password validation</title>
  <style>
    body { font-family: sans-serif; padding: 16px; }
    input { display: block; margin: 8px 0; padding: 8px; }
    .error { outline: 2px solid #dc2626; }
  </style>
</head>
<body>
  <form id="auth">
    <input type="password" placeholder="Enter password">
    <button type="submit">Sign in</button>
  </form>
  <script src="https://code.jquery.com/jquery-3.7.1.min.js"></script>
  <script>
    $("#auth").on("submit", function(e) {
      e.preventDefault();
      $("input:password", this).each(function() {
        $(this).toggleClass("error", !this.value);
      });
    });
  </script>
</body>
</html>

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