Error in main.js and main.js is generated from the wrong Visualforce page

Question

I have a Visualforce page which shows an error:

Uncaught TypeError: Cannot set property 'value' of null
at submitToSalesforce (main.js:55)

But when I update the visualforce page it does not update main.js. I am not sure how main.js is generated. One strange thing happening is that it seems to be pulling most of it's code from a separate Visualforce page than the one that's loaded. Another note that might be relevant is that handlebar.js is used on the page. Finally, this is a public facing visualforce page. I have a tool installed which shows a different color on chrome tabs for different orgs you are logged into. And the org in which i'm editing the visualforce page is a different color than when I view the page. I think it may have to do with it being a public facing visualforce page. I'm not sure how i can access the code for that page. I did see that it is a custom url in the 'site detail' section.

How is main.js generated?

Answer 1

Just a thought - it is possible that you have added some sort of incompatible JS library or plugin which "masks" methods or global variables with the same name that are auto-added by Visualforce as part of its normal operation. As a result, when Visualforce tries to do normal things, it errors out as seen above.