How to pass the term slug to the ajax function as a parameter [closed]

Question

this is the original code of the script

var $mainCat=$('#main_cat').val();

and i replaced it with this

 var $mainCat=$('#<how to pass the slug here>').val();

 echo '<ul>';
  foreach ($termchildren as $child) {
  $term = get_term_by( 'id', $child, $taxonomyName );
  echo '<li><a href="#" id=' .$term->slug. '>' . $term->name . ' </a></li>';
?>

<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.3.2/jquery.min.js" ></script>
<script type="text/javascript">
$(function()
{
  $('a#<?php echo $term->slug; ?>').click(function()
  {
    $('#pop-up1').show();
    $('#pop-up').show();
    <?php echo $term->slug; ?>
        var $mainCat=$('#<how to pass the slug here>').val();

now i need to pass the " a href " value i,e. term->slug to the variable $mainCat. How can i do it, kindly help me