function topnav_change(id, over) {
	if (over == true) {
		file = 'images/' + id + '_h.gif';
	} else {
		file = 'images/' + id + '.gif';
	}
	document.getElementById(id).src = file;
}
function buch_change(id, over) {
	if (over == true) {
		file = 'images/buchbox/' + id + '_h.jpg';
	} else {
		file = 'images/buchbox/' + id + '.jpg';
	}
	document.getElementById(id).src = file;
	for (var i = 1; i <= 8; i++) {
		document.getElementById('buch_' + i + '_desc').style.display = 'none';
	}
	if (over == true) {
		document.getElementById(id + '_desc').style.display = 'block';
	} else {
		document.getElementById(id + '_desc').style.display = 'none';
	}
}

/* Mail decryption */
function decryptThis(s) {
	var n=0;
	var r="mailto:";
	for(var i=0;i<s.length;i++) { 
		n=s.charCodeAt(i); 
		if (n>=8364) {n = 128;}
		r += String.fromCharCode(n-(2)); 
	}
	return r;
}

function doMailto(s) {
	location.href=decryptThis(s);
}

function viewdesc(id, over) {
	for (var i = 1; i <= 8; i++) {
		document.getElementById('buch_desc_foot_' + i).style.display = 'none';
	}
	if (over == true) {
		document.getElementById('buch_desc_' + id).style.display = 'block';
	} else {
		document.getElementById('buch_desc_' + id).style.display = 'none';
	}
}