var imgWidth = 35;
var imgHeight = 40;

if (document.images) {
aOn = new Image(imgWidth, imgHeight);
aOn.src = "img/a_red.gif";
aOff = new Image(imgWidth, imgHeight);
aOff.src = "img/a.gif";
bOn = new Image(imgWidth, imgHeight);
bOn.src = "img/b_red.gif";
bOff = new Image(imgWidth, imgHeight);
bOff.src = "img/b.gif";
cOn = new Image(imgWidth, imgHeight);
cOn.src = "img/c_red.gif";
cOff = new Image(imgWidth, imgHeight);
cOff.src = "img/c.gif";
dOn = new Image(imgWidth, imgHeight);
dOn.src = "img/d_red.gif";
dOff = new Image(imgWidth, imgHeight);
dOff.src = "img/d.gif";
eOn = new Image(imgWidth, imgHeight);
eOn.src = "img/e_red.gif";
eOff = new Image(imgWidth, imgHeight);
eOff.src = "img/e.gif";

fOn = new Image(imgWidth, imgHeight);
fOn.src = "img/f_red.gif";
fOff = new Image(imgWidth, imgHeight);
fOff.src = "img/f.gif";
gOn = new Image(imgWidth, imgHeight);
gOn.src = "img/g_red.gif";
gOff = new Image(imgWidth, imgHeight);
gOff.src = "img/g.gif";
hOn = new Image(imgWidth, imgHeight);
hOn.src = "img/h_red.gif";
hOff = new Image(imgWidth, imgHeight);
hOff.src = "img/h.gif";
iOn = new Image(imgWidth, imgHeight);
iOn.src = "img/i_red.gif";
iOff = new Image(imgWidth, imgHeight);
iOff.src = "img/i.gif";
jOn = new Image(imgWidth, imgHeight);
jOn.src = "img/j_red.gif";
jOff = new Image(imgWidth, imgHeight);
jOff.src = "img/j.gif";

kOn = new Image(imgWidth, imgHeight);
kOn.src = "img/k_red.gif";
kOff = new Image(imgWidth, imgHeight);
kOff.src = "img/k.gif";
lOn = new Image(imgWidth, imgHeight);
lOn.src = "img/l_red.gif";
lOff = new Image(imgWidth, imgHeight);
lOff.src = "img/l.gif";
mOn = new Image(imgWidth, imgHeight);
mOn.src = "img/m_red.gif";
mOff = new Image(imgWidth, imgHeight);
mOff.src = "img/m.gif";
nOn = new Image(imgWidth, imgHeight);
nOn.src = "img/n_red.gif";
nOff = new Image(imgWidth, imgHeight);
nOff.src = "img/n.gif";
oOn = new Image(imgWidth, imgHeight);
oOn.src = "img/o_red.gif";
oOff = new Image(imgWidth, imgHeight);
oOff.src = "img/o.gif";

pOn = new Image(imgWidth, imgHeight);
pOn.src = "img/p_red.gif";
pOff = new Image(imgWidth, imgHeight);
pOff.src = "img/p.gif";
qOn = new Image(imgWidth, imgHeight);
qOn.src = "img/q_red.gif";
qOff = new Image(imgWidth, imgHeight);
qOff.src = "img/q.gif";
rOn = new Image(imgWidth, imgHeight);
rOn.src = "img/r_red.gif";
rOff = new Image(imgWidth, imgHeight);
rOff.src = "img/r.gif";
sOn = new Image(imgWidth, imgHeight);
sOn.src = "img/s_red.gif";
sOff = new Image(imgWidth, imgHeight);
sOff.src = "img/s.gif";
tOn = new Image(imgWidth, imgHeight);
tOn.src = "img/t_red.gif";
tOff = new Image(imgWidth, imgHeight);
tOff.src = "img/t.gif";

uOn = new Image(imgWidth, imgHeight);
uOn.src = "img/u_red.gif";
uOff = new Image(imgWidth, imgHeight);
uOff.src = "img/u.gif";
vOn = new Image(imgWidth, imgHeight);
vOn.src = "img/v_red.gif";
vOff = new Image(imgWidth, imgHeight);
vOff.src = "img/v.gif";
wOn = new Image(imgWidth, imgHeight);
wOn.src = "img/w_red.gif";
wOff = new Image(imgWidth, imgHeight);
wOff.src = "img/w.gif";
xOn = new Image(imgWidth, imgHeight);
xOn.src = "img/x_red.gif";
xOff = new Image(imgWidth, imgHeight);
xOff.src = "img/x.gif";
yOn = new Image(imgWidth, imgHeight);
yOn.src = "img/y_red.gif";
yOff = new Image(imgWidth, imgHeight);
yOff.src = "img/y.gif";

zOn = new Image(imgWidth, imgHeight);
zOn.src = "img/z_red.gif";
zOff = new Image(imgWidth, imgHeight);
zOff.src = "img/z.gif";
}

function lightUp(imgName) {
	
	if (document.images) {
		
		imgOn = eval(imgName + "On.src");
		document[imgName].src = imgOn;
	}
}

function turnOff(imgName) {
	
	if (document.images) {
		
		imgOff = eval(imgName + "Off.src");
		document[imgName].src = imgOff;
	}
}