if (document.images) {            // Active Images
            img1on = new Image();      
            img1on.src = "button/about_us_over.gif";

            img2on = new Image();      
            img2on.src = "button/products_over.gif";
 
 	    img3on = new Image();      
            img3on.src = "button/contact_over.gif";

 	    img4on = new Image();      
            img4on.src = "button/home_over.gif";
           
            img5on = new Image();      
            img5on.src = "button/our_ingredients_over.gif";
            
            img6on = new Image(); 
            img6on.src = "button/harmful_chemicals_over.gif";
            
            img1off = new Image(); 
            img1off.src = "button/about_us.gif";

            img2off = new Image(); 
            img2off.src = "button/products.gif";
        
            img3off = new Image(); 
            img3off.src = "button/contact.gif";
        
	    img4off = new Image(); 
            img4off.src = "button/home.gif";
            
	    img5off = new Image(); 
            img5off.src = "button/our_ingredients.gif";
       
            img6off = new Image(); 
            img6off.src = "button/harmful_chemicals.gif";
       }

// Function to 'activate' images.
function imgOn(imgName) {
        if (document.images) {
            document[imgName].src = eval(imgName + "on.src");
        }
}

// Function to 'deactivate' images.
function imgOff(imgName) {
        if (document.images) {
            document[imgName].src = eval(imgName + "off.src");
        }
}