function checnum(as)
{
	var dd = as.value;
	if(isNaN(dd))
	{
		dd = dd.substring(0,(dd.length-1));
		as.value = dd;
	}		
}
function loan()
{
	var a = document.first.aa.value;
	var b = document.first.bb.value;
	var c = document.first.cc.value;
	var n = c * 12;
	var r = b/(12*100);
	var p = (a * r *Math.pow((1+r),n))/(Math.pow((1+r),n)-1);
	var prin = Math.round(p*100)/100;
	document.first.r1.value = prin;
	var mon = Math.round(((n * prin) - a)*100)/100;
	document.first.r2.value = mon;
	var tot = Math.round((mon/n)*100)/100;
	document.first.r3.value = tot;
	for(var i=0;i<n;i++)
	{
		var z = a * r * 1;
		var q = Math.round(z*100)/100;
		var t = p - z;
		var w = Math.round(t*100)/100;
		var e = a-t;
		var l = Math.round(e*100)/100;
		a=e;
	}
}
function clearbox(docname)
{
var totalrecords;

// obtain the count of records retrieved
totalrecords=6
for(i=0;i<totalrecords;i++)
docname[i].value="";
docname.area0.focus();
return false;
}