/**
 * show / hide filter options
 */
function filter_toggle(filter, toggler, fieldset) {

	/**
	 * switch current status
	 */
	switch (document.getElementById(filter).style.display) {

		/**
		 * filter shown - hide it, change toggler innerHTML and title, hide
		 * fieldset border
		 */
		case "block":
			document.getElementById(filter).style.display = "none";

			document.getElementById(toggler).innerHTML = "+ zobrazit filtr";
			document.getElementById(toggler).title = "Zobrazit možnosti filtrování";
			document.getElementById(toggler).blur();

			document.getElementById(fieldset).style.border = "none";
			document.getElementById(fieldset).style.padding = "0";
			break;

		/**
		 * filter hidden
		 */
		case "none":
			document.getElementById(filter).style.display = "block";

			document.getElementById(toggler).innerHTML = "- schovat filtr";
			document.getElementById(toggler).title = "Schovat možnosti filtrování";
			document.getElementById(toggler).blur();

			document.getElementById(fieldset).style.border = "1px #dedede solid";
			document.getElementById(fieldset).style.padding = "15px";
			break;
	}

	/**
	 * always return false
	 */
	return false;
}