How Do I Add Multiple Dynamic Dropdown Boxes to a GUI (Custom HTML Prompt action)

Continuing the discussion from Bootstrap 3 + Auto-Complete HTML Prompt Example:

I have tried to adapt DanThomas great example macro that shows how a GUI can be built using Javascript and KM's Custom HTML Prompt action.

Specifically I have 2 Dropdown Menus:
-- The first (Dropdown Menu) to select a CONTINENT.
-- The second (Dropdown Menu #2) to select a COUNTRY.

I am using the Javascript ONCHANGE action to have my choice in Dropdown Menu #1 of CONTINENT determine which choice list I get of COUNTRY's in Dropdown Menu #2 (using various KM Variables). (not working.)

e.g. It is supposed to just show the European COUNTRY's (by loading a KM Variable) if the CONTINENT chosen is Europe.

Can anyone point out my error? Dropdown Menu #2 choices are not being "changed" after the Javascript ONCHANGE. Thanks.

Form with Multiple DD (415.4 KB)

This is a pure JavaScript question. There may be some here who know the answer, but you're more likely to get a better/faster answer at

If you post a question there, probably best to leave out the KM part, and just ask how to use JavaScript on any HTML form.