version = navigator.appVersion.toLowerCase();
agent = navigator.userAgent.toLowerCase();
ie = (version.indexOf('msie')>-1);
win = (version.indexOf('windows')>-1);
opera = (agent.indexOf('opera')>-1);

function toggle_list(w) {
/*
 * Opens and closes folders (expandable sitemap)
 */
	ul=w.nextSibling.nextSibling.nextSibling;

	if(ul)
		if (ul.nodeName.toLowerCase()=="ul")
			if(ul.className=="off"){
				ul.className="on"
				w.className="open on"
			} else {
				ul.className="off"
				w.className="open off"
			}
	return false;
}

function toggle_display(id) {
/*
 * Shows and hides elements of the given Id
 */
	if (document.getElementById(id)) {
		if (document.getElementById(id).style.display == "block") {
			document.getElementById(id).style.display = "none";
		} else {
			document.getElementById(id).style.display = "block";
		}
	return true;
	} else {
	return false;
	}
}

function write_print(text) {
	document.write('\074a a  class="print" href=\"javascript:window.print();\"\076'+text+'\074/a\076');
}

function write_addtofavorite(text, URL, webname) {
	if ((opera) && (win)) return false;
	else if ((ie) && (win)) document.write('\074a class="AddToFavorite" href='+"'javascript:window.external.addFavorite(\""+URL+"\",\""+webname+"\")'"+'\"\076'+text+'\074/a\076 \074span\076|\074/span\076');
	return false;
}

function verify_contactform() {
  if (document.getElementById("mail_form_name").value=="") {
    alert("E-mail není možné odeslat - nezadali jste vaše jméno.");
    document.getElementById("mail_form_name").focus();
    return false;
  } else if (document.getElementById("mail_form_email").value=="") {
    alert("E-mail není možné odeslat - váš e-mail není zadán.");
    document.getElementById("mail_form_email").focus();
    return false;
  } else if (document.getElementById("mail_form_content").value=="") {
    alert("E-mail není možné odeslat - tělo zprávy je prázdné.");
    document.getElementById("mail_form_content").focus();
    return false;
  } else return true;
}

function verify_commentform() {
  if (document.getElementById("add_comment_comment").value=="") {
    alert("Vkládaný komentář je prázdný a tudíž nemohl být uložen. Opravte prosím jeho obsah a znovu jej odešlete.");
    document.getElementById("add_comment_comment").focus();
    return false;
  } else return true;
}

/*
 * Opens gallery picture
 */

function open_gallery_image(address) {
	width = 820;
	leftPos = (window.screen.width/2)-(width/2);
	height = (window.screen.height-400);
	topPos  = ((window.screen.height)/2)-(height/2)-30;
	close_gallery_image_window();
	return window.open(address, "image_window", "width="+width+", height="+height+", left="+leftPos+", top="+topPos+",dependent=yes, titlebar=no, scrollbars=yes, resizable=yes, status=no");
}

function close_gallery_image_window() {
	if (window.image_window && !window.image_window.closed)	image_window.close()
}