function PopUp(URL,popupname,b,h,scrollbars) {
	//alert( "PopUp(" + URL + popupname + b + h + scrollbars + ")" );
	var PopUpName = popupname || 'PopUp';
	var breite = b || 410;
	var hoehe = h || 450;
	var ScrollBars = scrollbars || 'auto';
	var xPos = (screen.availWidth - breite) / 2
	var yPos = (screen.availHeight - hoehe ) / 2
	if(popupname == 'tellafriend'){
		URL += '&loc='+window.location.href;
		URL += '&title='+document.title;
	}
	var fenster = window.open(URL,PopUpName,'width='+breite+',height='+hoehe+',scrollbars='+ScrollBars+',toolbar=no,menubar=no,screenX='+xPos+',screenY='+yPos+',left='+xPos+',top='+yPos)
	fenster.focus();
}