var last_block = '';

function display_blocks(block_id) {
	if (block_id != '' && document.getElementById(block_id).style.display == '') {
		hide_block(block_id);

		last_block = '';

		return;
	}

	if (last_block != '') {
		hide_block(last_block);
	}

	if (block_id != '') {
		document.getElementById(block_id).style.display = '';
	}

	last_block = block_id;
}

function hide_block(block_id) {
	if (block_id != '' && document.getElementById(block_id).style.display == '') {
		document.getElementById(block_id).style.display = 'none';
		return;
	}
}