Question

<script type="text/javascript">
$(function(){
 $('.update').click(function(){
  $.ajax({
     type: "POST",
     url: "/reporting_results/mark_result",
     data: "id="+$(this).attr("id")+"&check="+$(this).val()+"&user_id=<?=$user_id?>&product=<?=$this->uri->segment(3)?>",
  });
 return true
 });
});
</script>

Answer 1

Because of a trailing comma, right before the end of your $.ajax options:

 data: "id="+$(this).attr("id")+"&check="+$(this).val()+"&user_id=<?=$user_id?>&product=<?=$this->uri->segment(3)?>", <-- trailing comma, is why