Craig,
I have combined PHP + JS like this in the past
<script type="text/javascript">
// <![CDATA[
// jQuery calls start here. No need for $(document).ready() here.
<?php
for ($i = 0; $i < ($RepeatSelectionCounter_1 - 1); $i++) {
?>
$("#buyNow_<?php echo $i; ?>").click( function() {
if($(this).is(":checked") ) {
$("#qtyReq_<?php echo $i; ?>").removeAttr("disabled").val(1); // Removed $("#qty_0").val()+1
} else {
$("#qtyReq_<?php echo $i; ?>").attr("disabled", "disabled").val(0);
}
});
<?php
}
?>
// ]]>
</script>
Maybe that will help ?