function document_links( product_id ) {
  var loading = $( '.loading' );
  $.ajax({
    url:       '/global/scripts/document_links.php',
    data:      'product_id=' + product_id,
    dataType:  'json',
    beforeSend: function() {
      loading.each( function() { 
        $(this).show(); 
      });
    },
    success: function( json ) {
      var ul = $( '#document_links' );
      $.each( json[1], function( k, v ) {
        ul.append( '<li><a href="'+v.href+'">'+v.title+'</a></li>' );
      });
      ul.moreorless();
    },
    complete: function() {
      loading.each( function() { 
        $(this).hide(); 
      });
    }
  });
}