function checkPrev(){
  
var chk=0;

if(!document.getElementById("prev_nome").value){
chk=1;
}

if(!document.getElementById("prev_cognome").value){
chk=1;
}

if(!document.getElementById("prev_cap").value){
chk=1;
}

if(!document.getElementById("prev_via").value){
chk=1;
}

if(!document.getElementById("prev_citta").value){
chk=1;
}

if(!document.getElementById("prev_provincia").value){
chk=1;
}

if(!document.getElementById("prev_stato").value){
chk=1;
}

if(!document.getElementById("prev_email").value){
chk=1;
}

if(!document.getElementById("prev_telefono").value){
chk=1;
}

if(!document.getElementById("prev_privacy").checked){
chk=1;
}


if(!chk){
document.prev_form.submit();
}else{
alert("i campi contrassegnati da * sono obbligatori");
}
}