what is the problem if i got this notice saying:

Notice: Undefined index: 8 in C:\xampp\htdocs\projects\wesm\intranet\plugins\survey_manager\index.php on line 80

i'm using the jquery autocomplete..

here is some of my code for javascript in which the error occurred:

<script type='text/javascript'>
    var intranetUsers = ["<?php echo $content[0].' ", "';
        $num = 1;
        while($num != $getInranetUserCount['num']){
            echo $content[$num].'" , "';
            $num = $num + 1;
        }
            echo $content[$getInranetUserCount['num']];
    ?>"];


</script>

I've already use that code in some module and it works I don't know why it doesn't work this time.