Script loop on time sublist for Invocies

Hi All,

Pretty new to scripting (in particular Sublist) and getting an error when i try and update all time sublist lines on an Invoice after submit following create or edit of an invoice.

My script works if I hard code it for a single line but get an error when I try and loop it.

Below is the script I have simplified as much as possible:

function aftersubmit(type, form)
{
if (type == 'create' || type == 'edit')
{
var lineItemCount = nlapiGetLineItemCount('time');
for (var i= '1'; i<= lineItemCount; i++);
{
nlapiSetLineItemValue('time', 'amount', i, newamount);
nlapiSetLineItemValue('time', 'custcol_test', i, lineItemCount);