Código:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Documento sin título</title>
</head>
<body>
<form action="appletr.php" target="ChatVentana" name="chat" onsubmit="window.open('', 'ChatVentana', 'scrollbars=no,resizable=no,width=750,height=450,top=40,left=20')" method="post" id="chat">
<label>
<input type="text" name="email" id="email" />
</label>
<p>
<label>
<input type="submit" name="submit" id="submit" value="Enviar" />
</label>
</p>
</form>
</body>
</html>

