function changeImage(button)
			{
			document.images[button].src= button + "_down.png";
			return true;
			}
			function changeImageBack(button) 
			{
			 document.images[button].src = button + ".png";
			 return true;
			}

			// Copyright 2006-2007 javascript-array.com
			
			var timeout	= 250;
			var closetimer	= 0;
			var ddmenuitem	= 0;
			
			// open hidden layer
			function mopen(id)
			{	
				// cancel close timer
				mcancelclosetime();
			
				// close old layer
				if(ddmenuitem) ddmenuitem.style.visibility = 'hidden';
			
				// get new layer and show it
				ddmenuitem = document.getElementById(id);
				ddmenuitem.style.visibility = 'visible';
			
			}
			// close showed layer
			function mclose()
			{
				if(ddmenuitem) ddmenuitem.style.visibility = 'hidden';
			}
			
			// go close timer
			function mclosetime()
			{
				closetimer = window.setTimeout(mclose, timeout);
			}
			
			// cancel close timer
			function mcancelclosetime()
			{
				if(closetimer)
				{
					window.clearTimeout(closetimer);
					closetimer = null;
				}
			}
			
			// close layer when click-out
			document.onclick = mclose;