function show_over(region){
	document.getElementById('header_content').style.display = 'none';
	document.getElementById(region).style.display = 'block';
	document.getElementById("link_" + region).className = 'selected';
}
function show_out(region){
	document.getElementById('header_content').style.display = 'block';
	document.getElementById(region).style.display = 'none';
	document.getElementById("link_" + region).className = '';
}