if (document.images) {
            img1on = new Image();      
            img1on.src = "images/buttons/but_home_on.jpg"; 
			img2on = new Image();      
            img2on.src = "images/buttons/but_about_on.jpg"; 
			img3on = new Image();      
            img3on.src = "images/buttons/but_products_on.jpg"; 
			img4on = new Image();      
            img4on.src = "images/buttons/but_services_on.jpg";
            img5on = new Image();      
            img5on.src = "images/buttons/but_testimonials_on.jpg"; 
            img6on = new Image();      
            img6on.src = "images/buttons/but_contact_on.jpg"; 
       
            img1off = new Image(); 
            img1off.src = "images/buttons/but_home_off.jpg"; 
			img2off = new Image(); 
            img2off.src = "images/buttons/but_about_off.jpg"; 
			img3off = new Image(); 
            img3off.src = "images/buttons/but_products_off.jpg"; 
			img4off = new Image(); 
            img4off.src = "images/buttons/but_services_off.jpg"; 
            img5off = new Image(); 
            img5off.src = "images/buttons/but_testimonials_off.jpg";
            img6off = new Image(); 
            img6off.src = "images/buttons/but_contact_off.jpg";

		
        }
function imgOn(imgName) {
        if (document.images) {
            document[imgName].src = eval(imgName + "on.src");
        }
}
       
function imgOff(imgName) {
        if (document.images) {
            document[imgName].src = eval(imgName + "off.src");
        }
}