<script type="text/javascript" charset="utf-8">
  $(document).ready(function() {
 
    // Define the maximum answers per column
    var maxAnswers = 1;
 
    // Identify this question
    var thisQuestion = $('#question{QID}');
 
    // Index the array columns
    $('table.subquestion-list tr', thisQuestion).each(function(i) {
      $('> *', this).each(function(i) {
        $(this).attr('data-index', i);
      });
    });
 
    // Listener on the checkboxes
    $('input[type="checkbox"]', thisQuestion).on('change', function(e) {
      var thisIndex = $(this).closest('.answer-item').attr('data-index');
      $('[data-index="'+thisIndex+'"] input[type="checkbox"]', thisQuestion).prop('disabled', false);
 
      // If max reached, disable unchecked inputs in this column
      if($('[data-index="'+thisIndex+'"] input[type="checkbox"]:checked', thisQuestion).length >= maxAnswers) {
        $('[data-index="'+thisIndex+'"] input[type="checkbox"]:not(:checked)', thisQuestion).prop('disabled', true);
      }
    });
  });
</script>

<script type="text/javascript" charset="utf-8">
 
  $(document).ready(function() {
 
    // Define the maximum answers per row
    var maxAnswers = 3;
 
    // Identify this question
    var thisQuestion = $('#question{QID}');
 
    // Listener on the checkboxes
    $('input[type="checkbox"]', thisQuestion).on('change', function(e) {
      var thisRow = $(this).closest('tr');
      $('input[type="checkbox"]', thisRow).prop('disabled', false);
 
      // If max reached, disable unchecked inputs in this row
      if($('input[type="checkbox"]:checked', thisRow).length >= maxAnswers) {
        $('input[type="checkbox"]:not(:checked)', thisRow).prop('disabled', true);
      }
    });
  });  
</script>