function showTheme(id) {
	document.getElementById('overlaycontent').innerHTML='<img src="fileadmin/templates/welcome/images/maincontent'+id+'.jpg"/>';
	document.getElementById('overlaycontent').style.display='block';
}
function hideTheme() {
	document.getElementById('overlaycontent').innerHTML='';
	document.getElementById('overlaycontent').style.display='none';
}