if (document.images) {
image1on = new Image();  
image1on.src = "images/nbg_02.gif";  
image2on = new Image();  
image2on.src = "images/nbg_03.gif";  
image3on = new Image();  
image3on.src = "images/nbg_04.gif";  
image4on = new Image();  
image4on.src = "images/nbg_05.gif";  
image5on = new Image();  
image5on.src = "images/nbg_06.gif";  
image6on = new Image();  
image6on.src = "images/nbg_07.gif";  
image7on = new Image();  
image7on.src = "images/nbg_08.gif";  
image8on = new Image();  
image8on.src = "images/nbg_11.gif";  
image1off = new Image();
image1off.src = "images/nbg_02_on.gif";
image2off = new Image();
image2off.src = "images/nbg_03_on.gif";
image3off = new Image();
image3off.src = "images/nbg_04_on.gif";
image4off = new Image();
image4off.src = "images/nbg_05_on.gif";
image5off = new Image();
image5off.src = "images/nbg_06_on.gif";
image6off = new Image();
image6off.src = "images/nbg_07_on.gif";
image7off = new Image();
image7off.src = "images/nbg_08_on.gif";
image8off = new Image();
image8off.src = "images/nbg_11_on.gif";

}

function turnOn(imageName) {  
if (document.images) {    document[imageName].src = eval(imageName + "off.src");          
}

}

function turnOff(imageName) {  
if (document.images) {    document[imageName].src = eval(imageName + "on.src");
}

}