I'm only worried about 8, and all seems to work fine now - thanks.

Using the function supplied earlier, some of the numbers coming in are in the thousands, and have helpfully been formatted to include comma separators.
I found a snippet of javascript that removes commas, but it doesn't seem to work. Anyone care to have a go at explaining what I've done wrong this time? ;-)

<script type="text/javascript">
//Get the values from the table when checkboxes are checked
var getCheckboxes = function () {
    var i, elements = document.getElementsByTagName("input"),
        max = elements.length,
        result = [];
 
    for (i = 0; i < max; i += 1) {
        if (elements[i].type === "checkbox") {
            result.push(elements[i]);
        }
    }
    return result;
    DeleteComma(result);
};

<script type="text/javascript">
function DeleteComma(num) {
var temp1 = 0;
var xarray = num.split(",");
if ( xarray[2] != null ) {
   temp1 = xarray[0]+xarray[1]
+xarray[2]; return temp1 } 
else if ( xarray[1] != null ) {
          temp1 = xarray[0]
+xarray[1]; return temp1}
       else
{temp1 = xarray[0]; return temp1 }         
}
</script>

Um, that seems like a vastly over-complex function just for removing commas from a string.

var deleteCommas = function (num) {
    return (num + "").replace(/,/g, "");
};

But aside from that, you're calling DeleteComma() on the result of a function that generates a list of checkboxes. There are no commas to delete from such a list. Moreover, you'e calling it after the function has returned, so it never actually gets exectuted.

edit:
Looking over the code, the bit you need to change is this loop:

for (i = 0; i < max; i += 1) {
    if (checkBoxes[i].checked) {
        // Get values directly from table cells.
        total += +checkBoxes[i].parentElement.
            previousElementSibling.innerHTML;
        totalWholesale += +checkBoxes[i].parentElement.
            previousElementSibling.previousElementSibling.innerHTML;
    }
}

Change it to this:

var element, deleteCommas;
 
deleteCommas = function (num) {
    return (num + "").replace(/,/g, "");
}; 
 
for (i = 0; i < max; i += 1) {
    if (checkBoxes[i].checked) {
        element = checkBoxes[i].parentElement.previousSibling;
        total += +deleteCommas(element.innerHTML);
 
        element = element.previousSibling;
        totalWholesale += +deleteCommas(element.innerHTML);
    }
}

edit again:
Actually to make it even more resilient, you could change deleteCommas() to:

stripNonNumeric = function (num) {
    return (num + "").replace(/[^0-9.]/g, "");
};

That way it would remove things like currency symbols or extra spaces or whatnot - anything that isn't a digit or a .

Cheers - much appreciated once again!