function open_ctg(ctg_number) {
	document.getElementById('ctg' + ctg_number).style.visibility = 'visible';
}
function close_ctg(ctg_number) {
	document.getElementById('ctg' + ctg_number).style.visibility = 'hidden';
}

function swapImgRestore() {
	var i,x,a=document.sr;
	for(i=0; a && i < a.length && (x=a[i]) && x.oSrc; i++)
		x.src=x.oSrc;
}