toLowerCase Error #33
Description
Hi. I want to use ListBox element twice. While choosing the province in the first ListBox, I aim to select the district in the second. But after choosing the province, I get the error toLowerCase while trying to show the districts of the selected provinces in the other ListBox. Can you help me? As I understand there is a problem with the second listbox item. I'm adding the counties to the array but I'm having trouble trying to show them in the listbox.
Error line is bottom
My Javascript codes
