From: Andrew Koptyaev on
> Why your code didn't work as intended is not obvious from what you
> posted. As roundabout as it is, it would probably "work" (in an unsafe
> way). The error you describe might be caused when you try to add the new
> option to a select element.
>
> Try the "new Option" suggestion (first code snippet), and be careful
> about how you use "this".
>
>
> --
> stefan

Thank you. I just was wrong in add new option to select. I should use
appendChild.