var act = "b1";
	boff = new Image (); 
	boff.src = "../pics/blank.gif";
	
	bover = new Image (); 
	bover.src = "../pics/m1-over.gif";
	
	bon = new Image (); 
	bon.src = "../pics/m1-click.gif";
	
	function mover(imgName) 
		{
			if (act != imgName)
				{
					document [imgName].src = bover.src;
				}
		}

	function mout(imgName) 
		{
			if (act != imgName)
  				{
    					document [imgName].src = boff.src;
  				}
		}

	function mclick(imgName) 
		{
			if (act != "")
  				{
    					document [act].src = boff.src;
  				}
			document [imgName].src = bon.src;
			act = imgName;
		}
		
	function mclear() 
		{
			if (act != "")
  				{
    					document [act].src = boff.src;
  				}
  			act = "";
		}