function preloadImages()
{
	//images to preload
	var images = Array(
					   '/images/fr_over.gif',
					   '/images/en_over.gif',
					   '/images/de_over.gif',
					   '/images/description_fr_over.gif',
					   '/images/description_en_over.gif',
					   '/images/description_de_over.gif',
					   '/images/tree_arrow_expanded.gif',
					   '/images/tree_arrow_collapsed.gif',
					   '/images/en/luxembourg_over.gif',
					   '/images/en/contact_over.gif',
					   '/images/en/help_over.gif',
					   '/images/en/exit_over.gif',
					   '/images/en/button_search_company_over.gif',
					   '/images/en/button_search_product_over.gif',
					   '/images/en/button_search_nace_over.gif',
					   '/images/en/button_profile_over.gif',
					   '/images/en/add_to_bookmark_over.gif',
					   '/images/en/print_bookmark_over.gif',
					   '/images/fr/luxembourg_over.gif',
					   '/images/fr/contact_over.gif',
					   '/images/fr/help_over.gif',
					   '/images/fr/exit_over.gif',
					   '/images/fr/button_search_company_over.gif',
					   '/images/fr/button_search_product_over.gif',
					   '/images/fr/button_search_nace_over.gif',
					   '/images/fr/button_profile_over.gif',
					   '/images/fr/add_to_bookmark_over.gif',
					   '/images/fr/print_bookmark_over.gif',
					   '/images/de/luxembourg_over.gif',
					   '/images/de/contact_over.gif',
					   '/images/de/help_over.gif',
					   '/images/de/exit_over.gif',
					   '/images/de/button_search_company_over.gif',
					   '/images/de/button_search_product_over.gif',
					   '/images/de/button_search_nace_over.gif',
					   '/images/de/button_profile_over.gif',
					   '/images/de/add_to_bookmark_over.gif',
					   '/images/de/print_bookmark_over.gif'
					  );

	//preload images
	var image = Array;
	for (i = 0; i < images.length; i++)
	{
		image[i]     = new Image;
		image[i].src = images[i];
	}
}

function toggleVisibility(i)
{
	if (document.getElementById('list_row' + i).style.display == '')
	{
		document.getElementById('list_row' + i).style.display = 'none';
		document.getElementById('node' + i).src = '/images/tree_arrow_collapsed.gif';
	}
	else
	{
		document.getElementById('list_row' + i).style.display = '';
		document.getElementById('node' + i).src = '/images/tree_arrow_expanded.gif';
	}
}