function set_size() {
	document.getElementById('png').style.height=document.getElementById('container').offsetHeight + 'px';
	document.getElementById('png').style.width=document.getElementById('container').offsetWidth + 'px';
}

function show(i) {
	document.getElementById(i).style.display='block';
}

function hide(i) {
	document.getElementById(i).style.display='none';
}