If your form has semicolons, and your using jQuery, in order for it to work you have to use a double backslash for it to work:

This example, when executed, will copy the content from the billing input fields to the shipping input fields

<form>

<a href=”javascript: void(0);” id=”update_shipping_address_checkout”>Update Shipping</a>

<input type=”text” id=”shipping:firstname”>

<input type=”text” id=”shipping:lastname”>

<input type=”text” id=”billing:firstname”>

<input type=”text” id=”billing:lastname”>

</form>

<script type="text/javascript">
         jQuery(document).ready(function($) {
          $('#update_shipping_address_checkout').live('click', function() {
                var partsArray 	= new Array();
                $(':input.billing-data').each(function() {
                     // Split this, using the : as the key
                     // We are gathering information so we know what shipping input fields to populate
                     // Examples are firstname, lastname
                     partsArray = $(this).attr('id').split(':');
                     // The results are something like:
                     // partsArray[0] = billing
                     // partsArray[1] = firstname
                     // update the related shipping input
                    $( ':input.#shipping\\:' + partsArray[1] ).val( $(this).val() );
             });
         });
 });
</script>

To use jQuery in no conflict you can use:

<script type="text/javascript">
  $.noConflict();
  jQuery(document).ready(function($) {
    // Code that uses jQuery's $ can follow here.
  });
  // Code that uses other library's $ can follow here.
</script>