Originariamente inviato da Vincent.Zeno

non c'è "apertura e chiusura"
Si, invece. E' validato anche:

codice:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">

<head>
<title>Matematica</title>
</head>
<body>


Ciao

</br>  
</p>

</body>
</html>