if (document.images){

	mb1b = new Image();
	mb1b.src = "/img/_button1-on.jpg";
	mb2b = new Image();
	mb2b.src = "/img/_button2-on.jpg";
	mb3b = new Image();
	mb3b.src = "/img/_button3-on.jpg";
	mb4b = new Image();
	mb4b.src = "/img/_button4-on.jpg";
	mb5b = new Image();
	mb5b.src = "/img/_button5-on.jpg";

	mb1g = new Image();
	mb1g.src = "/img/_button1-off.jpg";
	mb2g = new Image();
	mb2g.src = "/img/_button2-off.jpg";
	mb3g = new Image();
	mb3g.src = "/img/_button3-off.jpg";
	mb4g = new Image();
	mb4g.src = "/img/_button4-off.jpg";
	mb5g = new Image();
	mb5g.src = "/img/_button5-off.jpg";
}

function on(imgname){
	if (document.images){
		document.images[imgname].src = eval ( imgname + 'b.src' )
	}
}

function off(imgname){
	if (document.images){
		document.images[imgname].src = eval ( imgname + 'g.src' )
	}
}