function ControllaForm() {

var email_reg_exp = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-]{2,})+\.)+([a-zA-Z0-9]{2,})+$/;
var controllo=false;

document.form1.nome.style.background = "#eeeeee";
document.form1.email.style.background = "#eeeeee";
document.form1.testo.style.background = "#eeeeee";
document.form1.check.style.background = "#ffffff";

if (document.form1.nome.value == "" )
{
controllo=true;
alert("Inserire il nome");
document.form1.nome.style.background = "#ffffaa";
document.form1.nome.focus();
}
else if (!email_reg_exp.test(document.form1.email.value) || (document.form1.email.value == "") || (document.form1.email.value == "undefined")) 
{
controllo=true;
alert("Inserire una email valida");
document.form1.email.style.background = "#ffffaa";
document.form1.email.focus();
}
else if (document.form1.testo.value == "" )
{
controllo=true;
alert("Inserire il testo");
document.form1.testo.style.background = "#ffffaa";
document.form1.testo.focus();
}
else if (document.form1.check.checked == false )
{
controllo=true;
alert("Autorizzare al trattamento dei dati personali");
document.form1.check.style.background = "#ffffaa";
document.form1.check.focus();
}

if (document.form1.nome.value != "" ) { document.form1.nome.style.background = "#ffffff"; }
if (email_reg_exp.test(document.form1.email.value) && document.form1.email.value != "" && document.form1.email.value != "undefined")  {
document.form1.email.style.background = "#ffffff";
}
if (document.form1.testo.value != "" ) { document.form1.testo.style.background = "#ffffff";  }
if (document.form1.check.checked == true ) { document.form1.check.style.background = "#ffffff";  }


if (controllo){ return false }else{ return true } 
}