Apparently TripAdvisor is aware of this issue, but has yet to do anything about it. Thankfully, the solution is rather simple.
The problem is with the link for www.jscache.com in the snippet of code that is auto-generated by TripAdvisor for the widget.
Copy the jscache.com link from the snippet of code, paste it into a web browser then copy the tripadvisor link that appears in the page (none of the other code is necessary). You will need to add an s to the http.
The next step is to fix the img src link by placing an s after the http there also.