Dropdown menues malfunction

Hello together!

At first: in combination with HiFiBerry, Volumio is just what I was looking for … As I had problems with the I2S drivers, I downloaded the 1.2beta from Github. And alright - the drivers are now functionally, but the dropdown menues as shown at the “settings” or “network” page in the WebUI won’t work any more. On every selection, the app tried to open a page with the URL “undefined” and resulted in an 404 HTML error. As software developer, I had no peace until I found the reason and a helpful solution. So I opened an issue in the GitHub repository (username “mamuesp” there) and posted a working solution. If wished, I could also checkin the changes, but this matter I would like to have approved here at first.

all the best,