var b_array = new Array();

function hid(num) {
	if(b_array[num] == false || b_array[num] == undefined) {
		document.getElementById('b' + num).className = 'opend';
		document.getElementById('bc' + num).className = 'vis';
		b_array[num] = true;
	} else {
		document.getElementById('b' + num).className = '';
		document.getElementById('bc' + num).className = 'hid';
		b_array[num] = false;
	}
}