var base="images/";
if (document.images) {            
        img1on=new Image();   img1on.src="images/btn_on_home.gif";
        img2on=new Image();   img2on.src="images/btn_on_news.gif";
        img3on=new Image();   img3on.src="images/btn_on_products.gif";
        img4on=new Image();   img4on.src="images/btn_on_services.gif";
        img5on=new Image();   img5on.src="images/btn_on_wireless.gif";
        img6on=new Image();   img6on.src="images/btn_on_contact.gif";
       
        img1off=new Image();  img1off.src="images/btn_home.gif";
        img2off=new Image();  img2off.src="images/btn_news.gif";
        img3off=new Image();  img3off.src="images/btn_products.gif";
        img4off=new Image();  img4off.src="images/btn_services.gif";
        img5off=new Image();  img5off.src="images/btn_wireless.gif";
        img6off=new Image();  img6off.src="images/btn_contact.gif";       
}

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");        
        }
}