Form with a checkbox group 'region' with items:
1|one[p1]
2|two[p1]
3|tree[p1]
4|four[p1]
5|five[p1]
6|six[p1]
7|seven[p1]
8|eight[p1]
9|nine[p1]
10|ten[p1]
and attribute: onclick="total();"

A calculation where totalRegion = {region:value}

And javascipt:
<script type="text/javascript">
function calculateTotal() {
var regioTot = document.getElementById("totaalRegio").value;
alert(regioTot);
}

</script>


When I select checkboxes, in
Safari & IE the value returned when clicking the first checkbox is 1,
2 when checking the 2nd checkbox, ...
But when doing the same with Chrome or FF, the 1st value is 0, the 2nd is 1.

Any idea what is wrong here and how to solve?