function hide(Num) {
	divname = "a" + Num;
	if (document.getElementById) {
		document.getElementById(divname).style.display='none';
	}
}

function show(Num) {
	divname = "a" + Num;
	if (document.getElementById) {
		document.getElementById(divname).style.display='block';
	}
}

function _switch(Num) {
	for (i=1; i <=26; i++) {
		if (Num != i) {
			hide(i)
		}
	else
		show(i);
	}
}