function switchSubContent(id) {
	total = document.getElementById('content_subnav').getElementsByTagName('li').length;	
	for (var i=1; i<=total; i++) {
		if ( i==id ) {
			document.getElementById('content_subnav'+i).className = 'content_subnav_selected';
			document.getElementById('subnav_content'+i).style.display = 'block';
		} else {
			document.getElementById('content_subnav'+i).className = '';
			document.getElementById('subnav_content'+i).style.display = 'none';
		}
	}	
}