function switchBlock(current_block_id, new_block_id)
{
	current_block = document.getElementById(current_block_id);
	new_block = document.getElementById(new_block_id);
	
	current_block.className += " invisible";
	new_block.className = new_block.className.replace(/(^|\s)invisible(\s|$)/, '');
	
	return false;
}