Button1On = new Image();
Button1On.src = "images/button1a.gif";
 
Button1Off = new Image();
Button1Off.src = "images/button1b.gif";

Button2On = new Image();
Button2On.src = "images/button2a.gif";

Button2Off = new Image();
Button2Off.src = "images/button2b.gif"; 
 
Button3On = new Image();
Button3On.src = "images/button3a.gif";

Button3Off = new Image();
Button3Off.src = "images/button3b.gif";
 
Button4On = new Image();
Button4On.src = "images/button4a.gif";

Button4Off = new Image();
Button4Off.src = "images/button4b.gif";

Button5On = new Image();
Button5On.src = "images/button5a.gif";

Button5Off = new Image();
Button5Off.src = "images/button5b.gif";

Button6On = new Image();
Button6On.src = "images/button_YP_a.gif";

Button6Off = new Image();
Button6Off.src = "images/button_YP_b.gif";

function OverImage(imageName)  {
 gotFocus = eval(imageName + "On.src");
 document [imageName].src = gotFocus;
   }

function OffImage(imageName)   {
 lostFocus = eval(imageName + "Off.src");
 document [imageName].src = lostFocus;
   
}