function leasauto()
   {
//lettura dati
  var c = parseFloat (document.form1.capitale.value);
  var u = parseFloat (document.form1.usato.value);
  var a = parseFloat (document.form1.anticipo.value);
  var f = parseFloat (document.form1.finale.value);
  var nr = parseFloat (document.form1.nr.value);
  var v = parseFloat (document.form1.aliq.value);
  var rata = parseFloat (document.form1.rata.value);

 
var iva = rata - (rata*100/(v+100))
var t= rata-iva;
var og = t - ((c-(u+a+f))/nr);
var tasso = ((og*2400) / ((c-(u+a))+f));
 document.form1.tot.value= Math.round(tasso*1000)/1000;
 document.form1.fin.value= (c-(u+a));
 document.form1.iva.value= Math.ceil(iva*1000)/1000;

}