function show_elements()
{
	document.getElementById('lightoff').className="off_show";
	document.getElementById('lighton').className="on_show";
	document.getElementById('ttl').className="title_show";
}

function lightisoff()
{
	document.getElementById('lightoff').style.zIndex="0";
	document.getElementById('lighton').style.zIndex="-1";

}

function lightison()
{
	document.getElementById('lighton').style.zIndex="0";
	document.getElementById('lightoff').style.zIndex="-1";
	
}