function tL(whichLayer)
	{
		var MyPic = 'im'+whichLayer;
		if (document.getElementById)
		{
			// this is the way the standards work
			var style2 = document.getElementById(whichLayer).style;
			style2.display = style2.display? "":"block";
			// do image swap
			var fullpath = document.getElementById(MyPic).src;
		   if ( fullpath.search('/img/Minus.jpg')>0 ) {
				document.getElementById(MyPic).src = '/img/Plus.jpg';
			}
			else {
				document.getElementById(MyPic).src = '/img/Minus.jpg';
			}
		}
		else if (document.all)
		{
			// this is the way old msie versions work
			var style2 = document.all[whichLayer].style;
			style2.display = style2.display? "":"block";
		}
		else if (document.layers)
		{
			// this is the way nn4 works
			var style2 = document.layers[whichLayer].style;
			style2.display = style2.display? "":"block";
		}
	}