var NavBar = new Array();
// len improve.
var len = 9;	

for (i = 0; i <len; i++)
{
	s = 'menu' + (i*2);
	NavBar[i*2] = document.getElementById(s).style;
	NavBar[i*2].visibility = 'visible';
	s = 'menu' + (i*2+1);
	NavBar[i*2+1] = document.getElementById(s).style;
	NavBar[i*2+1].display = 'none';
}

function showLayer(l,img)
{
	if (l.display =='block'){  
		l.display='none';
		img.src="../images/plus.gif";
	}
	else {
		l.display='block';
		img.src="../images/minus.gif";
	}
}