if (document.images) {
	buttonup = new Image();
	buttonup.src = 'gfx/gbk1.gif';
	buttonover = new Image();
	buttonover.src = 'gfx/gbk2.gif';
	buttondown = new Image();
	buttondown.src = 'gfx/gbk3.gif';
}

function mouseout(imagename) {
	if (document.images) {
		document[imagename].src = eval(imagename+'up.src');
	}
}

function mouseover(imagename) {
	if (document.images) {
		document[imagename].src = eval(imagename+'over.src');
	}
}

function mousedown(imagename) {
	if (document.images) {
		document[imagename].src = eval(imagename+'down.src');
	}
}