function ani() {
	var i = parseFloat(document.form1.tasso.value);
	var m = parseInt (document.form1.versamenti.value);
   	var a = parseInt(document.form1.anni.value);
   	var t = parseInt(document.form1.modo.value);
   	var w = a*m;
	if(t==2) var ani = ((1-Math.pow((1+((i/100)/m)),-w))/((i/100)/m))
	else var ani = ((1-Math.pow((1+((i/100)/m)),-w))/((i/100)/m))*(1+((i/100)/m))
	document.form1.tot.value = Math.round(ani*1000)/1000;
}