I keep getting a NaN on this form-based calculator I am trying to make... I can't figure out what I am doing wrong. Any input, or in this case "output", would be greatly appreciated. Here is the code:

Code:
<script type="text/javascript">

function calculateBudget()
{
var totalBudget = document.getElementById('TotalBudget');
var listCost = document.getElementById('ListCost');
var postage = document.getElementById('Postage');
var printing = document.getElementById('Printing');
var uses = document.getElementById('Uses');

var totalRecords = document.getElementById('TotalRecords');

totalBudget = parseFloat(totalBudget);
listCost = parseFloat(listCost);
postage = parseFloat(postage);
printing = parseFloat(printing);
uses = parseFloat(uses);

var result1 = postage + printing;
var result2 = result1 * uses + listCost;
var result3 = listCost / result2;
var result4 = totalBudget * result3;

totalRecords.value = 0;
totalRecords.value = parseFloat(totalRecords.value);
totalRecords.value = parseFloat(totalRecords.value) + result4 / listCost;
}
</script>