What exactly are you trying to do with their IDs other than confirm they have one, and it is valid? I'm not sure based on what you are describing why support would say you need JS and not an Authenticator step, unless there's more to what you need than is described.
Do you have the list of valid IDs? If so, it sounds like if you load the list with the "ID" field as "ExternalDataReference" (I would probably have the data in the file twice, once as ID and once as ExternalDataReference, but that is just me), then you can use an authenticator step in your survey flow. Then depending what your next steps are you can either let them continue through the survey or not, or access different "paths" in the survey, or not, or flag a field for "Validated" or not, based on whether they have successfully authenticated a valid ID. (Note that each ID can only authenticate once, so for testing purposes, I would add a few "fake" IDs in the file so you can test with them.)

https://community.qualtrics.com/XMcommunity/discussion/comment/45447#Comment_45447HI CarolK

Thank you very much for your response.
The use of an authenticator would work, but it shows up as a password needed to continue and that is the experience we want the respondent to have. If I could edit the page that shows up when using an authenticator then it would be acceptable.

Oh, you can customize the content on the page, by using custom messages.
For example:
Authentication step. Note that I didn't select Password OR Pre-fill, they aren't required but are available if needed. For your example, I set the EDR to be labeled on the form as ID:
Options on the authenticator step. I set Options to use a custom message for both the prompt (to ask for an ID) and for the error (to make it clear it's the ID that they are failing on):
We have our look and feel applied but below is how that page now displays in my example. Obviously, I could have put more content ahead of "Please enter your ID number." -- a whole introduction etc if needed, but I kept it basic for this example.
In my example, they can try 3 times before I'm going to path them out (out of the survey or to another, alternative path, whatever), so I also created a custom error message for those tries:
Hopefully some of that will help. If not, there are a lot of JS experts here, I'm just not one of them!
:) Good luck!

https://community.qualtrics.com/XMcommunity/discussion/comment/45450#Comment_45450CarolK

That is awesome. Thank you.