prev = null;

function sh(id) {
	el = document.getElementById(id);

	if(el.className == 'sm visible') {
		el.className = 'sm hidden';
	} else {
		if(prev) {
			prev.className = 'sm hidden';
		}
		el.className = 'sm visible';
		prev = el;
	}
	
	if(window.opera) {
		document.getElementById('head3').style.marginTop='-1px';
		setTimeout("document.getElementById('head3').style.marginTop=0;",20);
	}
}

function ec(id) {
	el = document.getElementById(id);

	if(el.className == 'visible') {
		el.className = 'hidden';
	} else {
		el.className = 'visible';
	}
}