Google图表中的PHP字符串连接

I am passing PHP session variables to a Google chart object. The following works fine:

      function drawChart() {

    var data = google.visualization.arrayToDataTable([
      ['Descriptor', 'Items checked/Total number of items', { role: 'annotation' }],
      ['Attention', <?php echo $_SESSION["A"];?>, <?php echo $_SESSION["A"];?>],
      ['Auditory', <?php echo $_SESSION["AUD"];?>, <?php echo $_SESSION["AUD"];?>]           
  ]);

Everything works fine when the $_SESSION["A"] variable is by itself, and will print an interger in the chart ie. 12. However, when I try to concatenate '/12' to the $_SESSION["A"] variable in hopes of echoing '12/12' in the chart, I end up getting '1' in the chart (it is doing the math on 12/12). Here is the faulty code:

      function drawChart() {

    var data = google.visualization.arrayToDataTable([
      ['Descriptor', 'Items checked/Total number of items', { role: 'annotation' }],
      ['Attention', <?php echo $_SESSION["A"];?>, <?php echo $_SESSION["A"]."/12";?>],
      ['Auditory', <?php echo $_SESSION["AUD"];?>, <?php echo $_SESSION["AUD"]."/12";?>]           
  ]);

How do I concatenate "/12" to an integer without it doing the math?

put single quotes so that js does not make the math and treat the value as a string instead:

['Auditory', <?php echo $_SESSION["AUD"];?>, '<?php echo $_SESSION["AUD"]."/12";?>']