function offneFenster(fensterURL,fensterW,fensterH) {
	var fensterX = ((screen.availWidth - fensterW)/2);
	var fensterY = ((screen.availHeight - fensterH)/2-10);
	if(screen.height <= 600 && fensterH > 530) {
		fensterH = 530;
	}
	window.open(fensterURL,'_blank','width='+fensterW+',height='+fensterH+',top='+fensterY+',left='+fensterX+',toolbar=no,location=no,status=no,menubar=no,scrollbars=yes,resizable=no,fullscreen=no');
}

function isIE() {
	return (navigator.userAgent.indexOf('MSIE') > 0);
}

function checkMail(email) {
    at = email.indexOf("@");
    if (at <= 0 || email.substring(at).indexOf(".") < 3) {
		return false;
    }
    return true;
}

function clearTextIf(e, tbc) {
        if (e.value == tbc) e.value = '';
}

function setIfEmpty(e, tbc) {
        if (e.value == "") e.value = tbc;
}