if (document.images) {
	var viviteoff = new Image();
	viviteoff.src = "Images/botom_left.jpg";
   	viviteon = new Image();
    viviteon.src = "Images/botom_lefton.jpg";
	
	var prevageoff = new Image();
	prevageoff.src = "Images/botom_right_top.jpg";
   	prevageon = new Image();
    prevageon.src = "Images/botom_right_topon.jpg";
	
	var mdforteoff = new Image();
	mdforteoff.src = "Images/botom_right_btm.jpg";
   	mdforteon = new Image();
  	mdforteon.src = "Images/botom_right_btmon.jpg";
	
}

function act(imgName) {
	document.images[imgName].src = eval(imgName + 'on.src');
}

function inact(imgName,imgLayer) {
	document.images[imgName].src = eval(imgName + 'off.src');
}