sheet.bind(GC.Spread.Sheets.Events.LeftColumnChanged,function(event,data)
  {
    var str = "----------------------------------------\n";
    var title = "Event [LeftColumnChanged ] Fired";
    str = str.substr(0, 4) + title + str.substr(4 + title.length);
    if (typeof data == "object") {
        for (var key in data) {
            str += key + " : " + data[key] + "\n";
          }
      } else {
        str += data + "\n";
      }
      alert(str);
  });
sheet.bind(GC.Spread.Sheets.Events.TopRowChanged,function(event,data)
  {
        var str = "----------------------------------------\n";
        var title = "Event [TopRowChanged] Fired";
        str = str.substr(0, 4) + title + str.substr(4 + title.length);
        if (typeof data == "object") {
            for (var key in data) {
                str += key + " : " + data[key] + "\n";
            }
        } else {
            str += data + "\n";
        }
        alert(str);
    });