function checkrequired1(which){
// Variabili associate ai campi del modulo
var email = document.frmnl.emailnl.value; 
var email_reg_exp = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-]{2,})+\.)+([a-zA-Z0-9]{2,})+$/; 


if (!email_reg_exp.test(email) || (email == "") || (email == "undefined")) {
alert("Indicare il campo Email.");
document.frmnl.emailnl.select();
return false;
}


}




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