How to call a function in the C3 HTML Element?

I'm using C3's HTML Element to display content. I have data stored in an array, I want to call the function in the HTML Element if array.at(0) is 1.

I've tried this method but it doesn't work, I might doing it wrong.

runtime.objects.LevelDropdown.getFirstInstance().contentwindow.updateTransportLevelDropdown(1)

LevelDropdown is the HTML Element

updateTransportLevelDropdown() is the function within the HTML Element

Can anyone help?

Thank you.

I found the solution. Below works perfectly.

-> Browser: Execute javascript "updateTransportLevelDropdown('1');"