if (document.images) { 

var img1on = new Image();
img1on.src = "img/menu1_1.gif"; 
var img1off = new Image();
img1off.src = "img/menu1_2.gif";

var img2on = new Image();
img2on.src = "img/menu3_3.gif"; 
var img2off = new Image();
img2off.src = "img/menu3_4.gif";

var img3on = new Image();
img3on.src = "img/menu4_3.gif"; 
var img3off = new Image();
img3off.src = "img/menu4_4.gif";

var img4on = new Image();
img4on.src = "img/menu5_1.gif"; 
var img4off = new Image();
img4off.src = "img/menu5_2.gif";

var img5on = new Image();
img5on.src = "img/menu6_1.gif"; 
var img5off = new Image();
img5off.src = "img/menu6_2.gif";


} 


function On(name) { 

if (document.images) { 
document.images[name].src = eval(name + 'on.src'); 
} 

} 

function Off(name) { 

if (document.images) { 
document.images[name].src = eval(name + 'off.src'); 
} 

}