var timer=new Object;

function on(which)
{
	if (!document.getElementById)
		return;

	e=document.getElementById(which);
	
	if (e)
		e.src=e.src.replace(/.png$/, '_on.png');
}

function off(which)
{
	if (!document.getElementById)
		return;

	e=document.getElementById(which);
	
	if (e)
		e.src=e.src.replace(/_on.png$/, '.png');
}