if (document.images) {

//rollovers
		home = new Image();
		home_down = new Image();
		where = new Image();
		where_down = new Image();
		about_pb = new Image();
		about_pb_down = new Image();
		risk = new Image();
		risk_down = new Image();
		action = new Image();
		action_down = new Image();
		about_wwf = new Image();
		about_wwf_down = new Image();

//descriptors
		default_desc = new Image();
		home_desc = new Image();
		where_desc = new Image();
		about_pb_desc = new Image();
		risk_desc = new Image();
		action_desc = new Image();
		about_wwf_desc = new Image();

//rollovers
		home.src = "_images/btn-home-0.gif";
		home_down.src = "_images/btn-home-1.gif";
		where.src = "_images/btn-where-0.gif";
		where_down.src = "_images/btn-where-1.gif";
		about_pb.src = "_images/btn-about_pb-0.gif";
		about_pb_down.src = "_images/btn-about_pb-1.gif";
		risk.src = "_images/btn-risk-0.gif";
		risk_down.src = "_images/btn-risk-1.gif";
		action.src = "_images/btn-action-0.gif";
		action_down.src = "_images/btn-action-1.gif";
		about_wwf.src = "_images/btn-about_wwf-0.gif";
		about_wwf_down.src = "_images/btn-about_wwf-1.gif";

//descriptors
		default_desc.src = "_images/img-desc-blank.gif";
		home_desc.src = "_images/img-desc-blank.gif";
		where_desc.src = "_images/img-desc-where.gif";
		about_pb_desc.src = "_images/img-desc-about_pb.gif";
		risk_desc.src = "_images/img-desc-risk.gif";
		action_desc.src = "_images/img-desc-action.gif";
		about_wwf_desc.src = "_images/img-desc-about_wwf.gif";

}

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

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