var lastid = -1;

function showMe(id){
	if(lastid > -1) {
		articles[lastid].style.display = 'none';
	}
	if(lastid != id){
		articles[id].style.display = 'block';
		lastid = id;
	} else {
		lastid = -1;
	}
}

function hideAll(){
	for(var article in articles){
		articles[article].style.display = 'none';
	}
}