function titoli()
{
var quo = parseFloat(document.form1.quotazione.value);
var val = parseFloat(document.form1.valore.value);
var num = parseFloat(document.form1.numero.value);
var diff = ((quo/val)-1)*100;
var con = (quo*num);
 if (isNaN(diff)) 
   alert("Not at Number!"); 
 if (isNaN(con)) 
   alert("Not at Number!"); 
document.form1.tot.value = (Math.round(diff*100)/100)+"%";
document.form1.pop.value = Math.round(con*100)/100;
}