if (document.images) {

//rollovers
		about = new Image();
		about_down = new Image();
		portfolio = new Image();
		portfolio_down = new Image();
		testimonials = new Image();
		testimonials_down = new Image();
		network = new Image();
		network_down = new Image();
		consultants = new Image();
		consultants_down = new Image();
		contact = new Image();
		contact_down = new Image();

//rollovers
		about.src = "_images/btn-sub-about-0.gif";
		about_down.src = "_images/btn-sub-about-1.gif";
		portfolio.src = "_images/btn-sub-portfolio-0.gif";
		portfolio_down.src = "_images/btn-sub-portfolio-1.gif";
		testimonials.src = "_images/btn-sub-testimonials-0.gif";
		testimonials_down.src = "_images/btn-sub-testimonials-1.gif";
		network.src = "_images/btn-sub-network-0.gif";
		network_down.src = "_images/btn-sub-network-1.gif";
		consultants.src = "_images/btn-sub-consultants-0.gif";
		consultants_down.src = "_images/btn-sub-consultants-1.gif";
		contact.src = "_images/btn-sub-contact-0.gif";
		contact_down.src = "_images/btn-sub-contact-1.gif";

}

function buttonOn(imageName) {
	if (document.images) {
		document[imageName].src = eval(imageName+"_down.src")
		}
	}

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