function switch_image(id, img) {
	document.getElementById(id).src = img;
}
function show_tooltips(id, mode, cnt) {
	i = 0;
	while(i < cnt) {
		i++;
		document.getElementById('tool-'+i).style.visibility = 'hidden';
	}
	
	if(mode == "show") {
		document.getElementById('tool-'+id).style.visibility = 'visible';
	}
	else {
		document.getElementById('tool-'+id).style.visibility = 'hidden';			
	}
}