function showhide(id) {
	var helperid = "kat_" + id;
	if (document.getElementById(id).style.visibility != 'visible') {
		document.getElementById(id).style.visibility = 'visible';
		document.getElementById(id).style.position = 'static';
		document.getElementById(helperid).style.backgroundImage = 'url(../img/frame/twunten.gif)';
		document.getElementById(helperid).style.backgroundPosition = '0px 5px';
	} else {
		document.getElementById(id).style.visibility = 'hidden';
		document.getElementById(id).style.position = 'absolute';
		document.getElementById(helperid).style.backgroundImage = 'url(../img/frame/twrechts.gif)';
		document.getElementById(helperid).style.backgroundPosition = '0px 0px';
	}
}