function wastage() {
var volume = document.forms.calc.volume.value;
if (volume == '') {alert('Enter the number of addresses you are mailing.');
document.forms.calc.volume.focus();return false;}

var pack = document.forms.calc.pack.value;
if (pack == '') {alert('Enter the cost of each mailing pack.');
document.forms.calc.pack.focus();return false;}

var error = .10;

var mailings = document.forms.calc.mailings.value;
if (mailings == '') {alert('Enter number of mailings per year.');
document.forms.calc.mailings.focus();return false;}
var waste = (volume * error);
var wastepermailing = (volume * error) * pack;
var wasteperyear = wastepermailing * mailings;
document.forms.calc.waste.value = Math.floor(waste);
document.forms.calc.wastepermailing.value = Math.floor(wastepermailing);
document.forms.calc.wasteperyear.value = Math.floor(wasteperyear);
return false;
}