function Billboard_ShowBlock(code, change) {
  var num = wx.GetData('block' + code + 'number');
  var row = wx.GetData('block' + code + 'row');
  var idx = wx.GetData('block' + code + 'index') + change;
  
  if (idx < 0) idx = num - 1;
  if (idx > (num - 1)) idx = 0;

  var index = idx - 1;
  for (var i=0; i<row; i++) {
    index++;
    if (index < 0) index = num - 1;
    if (index > (num - 1)) index = 0;
    
    var data = wx.GetData('block' + code + 'd' + index);
    if (obj = document.getElementById('idBlock' + code + 'Title' + i)) obj.innerHTML = data[0];
    if (obj = document.getElementById('idBlock' + code + 'Message' + i)) obj.innerHTML = data[1];
  }
  
  wx.AddData('block' + code + 'index', idx);
}