Ecco l'html:

codice:
                       <form class="form-horizontal" id="registra" name="registra" action='registrazione_effettuata.php' method="POST">
                            <fieldset>
                            <div id="legend">
                            <legend class="">Registrati</legend>
                            </div>
                                
                            
                            <div class="control-group">                                 
                            <label class="control-label" for="nome">Nome</label>
                            <div class="controls">
                            <input type="text" id="nome" name="nome" class="input-xlarge">
                            </div>
                            </div>
                                
                             
                            <div class="control-group">                            
                            <label class="control-label" for="cognome">Cognome</label>
                            <div class="controls">
                            <input type="text" id="cognome" name="cognome"  class="input-xlarge">
                            </div>
                            </div>
                            
                            
                            <div class="control-group">                           
                            <label class="control-label" for="indirizzo">Indirizzo</label>
                            <div class="controls">
                            <input type="text" id="indirizzo" name="indirizzo"  class="input-xlarge">
                            </div>
                            </div>
                            
                             
                            <div class="control-group">                            
                            <label class="control-label" for="citta">Citta&grave;</label>
                            <div class="controls">
                            <input type="text" id="citta" name="citta"  class="input-xlarge">
                            </div>
                            </div>
                            
                            
                            <div class="control-group">                            
                            <label class="control-label" for="provincia">Provincia</label>
                            <div class="controls">
                            <input type="text" id="provincia" name="provincia"  class="input-xlarge">
                            </div>
                            </div>
                                
                            
                            <div class="control-group">                            
                            <label class="control-label" for="cap">C.A.P.</label>
                            <div class="controls">
                            <input type="text" id="cap" name="cap"  class="input-xlarge">
                            </div>
                            </div>
                            
                           
                            <div class="control-group">                           
                            <label class="control-label" for="email">E-mail</label>
                            <div class="controls">
                            <input type="text" id="email" name="email"  class="input-xlarge">
                             </div>
                            </div>
                            
                            
                            <div class="control-group">                           
                            <label class="control-label" for="username">Username</label>
                            <div class="controls">
                            <input type="text" id="username" name="username"  class="input-xlarge">                            
                            </div>
                            </div>
                            
                            
                            <div class="control-group">                            
                            <label class="control-label" for="password">Password</label>
                            <div class="controls">
                            <input type="password" id="pw1" name="pw1"  class="input-xlarge">                            
                            </div>
                            </div>

                           
                            <div class="control-group">                            
                            <label class="control-label" for="password_confirm">Password (Confirm)</label>
                            <div class="controls">
                            <input type="password" id="pw2" name="pw2"  class="input-xlarge">                            
                            </div>
                            </div>

                            <div class="control-group">
                           <div class="controls">
                            <input type="submit" class="btn btn-success" value="Registra">
                            </div>
                            </div>
                            </fieldset>
                   </form>