Javascript not loading for some users?

Hello,
I am currently running an online study that uses custom HTML and Javascript in Qualtrics. When testing my code, everything looked fine and many people have been able to complete the study,
However, a few participants expressed confusion about the question that uses javascript code. I figured out that the HTML elements loaded fine, but the Javascript code just did not load (basically, when I removed my javascript code, I would get the same look as they got).
For reference, here is the code that I used (both HTML and javascript) https://github.com/joyfulwei/Balloon-task-in-Qualtrics and an example of how it should look like (except my balloon is red): https://erasmusuniversity.eu.qualtrics.com/jfe/preview/SV_6WfiO2c5PXQIm6p?Q_SurveyVersionID=current&Q_CHL=preview
I also have attached a picture of the incorrect display that some participants saw.
Any help on this would be appreciated, my experience with both HTML and Javascript is very limited.