<script language='JavaScript' src='js/menutop.js'></script>
if (screen.width > 699) { echo "<script language='JavaScript' src='js/menutop.js'>"; }
<center> <form action='php/login.php' method='post' name='login'> <h1>Login</h1> <input type='email' name='user_email'> <input type='password' name='user_password'> <input type='submit' name='submit' value='Login'> </form> </center>