function isNumberKey(evt)
      {
         var charCode = (evt.which) ? evt.which : event.keyCode
         if ((charCode > 31 && (charCode < 48 || charCode > 57))&&(charCode != 46))
            return false;

         return true;
      }

function numRound(nStr){
	var nr = nStr.toFixed(0);
	return nr;
	}
function addCommas(nStr){
   nStr += '';
   x = nStr.split('.');
   x1 = x[0];
   x2 = x.length > 1 ? '.' + x[1] : '';
   var rgx = /(\d+)(\d{3})/;
   while (rgx.test(x1)) {
   x1 = x1.replace(rgx, '$1' + ',' + '$2');
  }
  return x1 + x2;
}
function calc(){
	var nos = document.getElementById('nos').value;
	var noa = document.getElementById('noa').value;
	var cps = document.getElementById('cps').value;
	
	var week = nos*noa*cps;
	document.getElementById('week').innerHTML = '&pound;'+addCommas(numRound(week));
	
	var month = week*4;
	document.getElementById('month').innerHTML = '&pound;'+addCommas(numRound(month));
	
	var year = week*52;
	document.getElementById('year').innerHTML = '&pound;'+addCommas(numRound(year));
	
	var l1 = 9490;
	var l2 = 15584;
	var l3 = 19621;
	var l4 = 23659;
	var l5 = 26696;
	var l6 = 30733;
	var l7 = 34770;
	var l8 = 38807;
	
	document.getElementById('w1').innerHTML = addCommas(numRound(l1/week))+' wks';
	document.getElementById('m1').innerHTML = addCommas(numRound(l1/month))+' mths';
	document.getElementById('w2').innerHTML = addCommas(numRound(l2/week))+' wks';
	document.getElementById('m2').innerHTML = addCommas(numRound(l2/month))+' mths';
	document.getElementById('w3').innerHTML = addCommas(numRound(l3/week))+' wks';
	document.getElementById('m3').innerHTML = addCommas(numRound(l3/month))+' mths';
	document.getElementById('w4').innerHTML = addCommas(numRound(l4/week))+' wks';
	document.getElementById('m4').innerHTML = addCommas(numRound(l4/month))+' mths';
	document.getElementById('w5').innerHTML = addCommas(numRound(l5/week))+' wks';
	document.getElementById('m5').innerHTML = addCommas(numRound(l5/month))+' mths';
	document.getElementById('w6').innerHTML = addCommas(numRound(l6/week))+' wks';
	document.getElementById('m6').innerHTML = addCommas(numRound(l6/month))+' mths';
	document.getElementById('w7').innerHTML = addCommas(numRound(l7/week))+' wks';
	document.getElementById('m7').innerHTML = addCommas(numRound(l7/month))+' mths';
	document.getElementById('w8').innerHTML = addCommas(numRound(l8/week))+' wks';
	document.getElementById('m8').innerHTML = addCommas(numRound(l8/month))+' mths';
}