Login.html

<html>
    <head>
      <link rel="stylesheet" href="estilo_login.css">
      <meta name="viewport" http-equiv="Content-Type" content="width=device-width, initial-scale=1" charset="UTF-8" />
      <title>Decide YT | Inicio de Sesión</title>
      <script  type="text/javascript" src=login.js ></script>
    </head>
    
    <body>
      <div class="main" id="form">
        <p class="sign"> Inicio de Sesión</p>
        <form class="form1" id="inicio">
          <input class="un"  type="text" align="center" placeholder="Usuario" id="uname" required><br>
          <input class="pass" type="password" align="center" placeholder="Contraseña" id="pass" required>
          <br><br>
          <a class="submit" href="javascript:;" onclick="validateForm()" align="center">Iniciar Sesión</a>
          <br>
          <a class="register" align="center" href="Register.html">Registrarse</a>
          <p class="warnings" id="warnings"></p>
        </div>
        <script src="avisoslogin.js"></script>  
    </body>
    
</html>    