class name as variable

[gintare]

How to use Jquery variable as css selector?

For instance,

<script>
$(document).ready(function(){
  var ind='th78'; //database row index
  var classname='highlight ' + ind;
  spanNode.className = classname; // set css
  $(".highlight.ind").append("text from database with id=ind");
  })
// this does not work because there should be not word "ind", but value of variable ind. How to select value of variable ind?

//OR
var spanNode = document.createElement('span');
var ind='th78'; //database row index
spanNode.id=ind;
 $("[#id=ind]").append("text from database with id=ind");
//This also does not work, because instead of ind, i have to compare with variable ind. How to use value of variable ind?
</script>

I do not know how to use value of variable as Jquery/css selector.

[gintare]

Working example:

http://stackoverflow.com/questions/4823339/using-variables-within-a-jquery-selector

they just add variable:
$('#'+ section_id + ' ul').children() .size();

In my case it would be:
ind='th78';
$('span').attr( 'id', ind );
$("#"+ind).appe nd("text from database with id=ind");