Hey Alan! Welcome to the Community! Do you mind sharing both your read-only link (see how here) and your published (domain.webflow.io link), and let me know which page you have the form with the custom attribute?
Thanks for responding on a Sunday! The read-only and published links are below. The form will be on most pages so is set up as a symbol. I initially thought that might be an issue so I unlinked it but the same problem persisted.
Hoping someone else can figure out why the attribute isn’t being added natively with Webflow, but the code above should get you taken care of. It says: on page load, add the attribute to the select dropdown (targeted by using the ID you already have on the element.)
Thanks for getting back so quickly. That solution works and will be enough to show the client to push it over the line. It’s rare that I have to use the custom attribute but thought I better flag it either way.
Just flagging that I’m having the exact same issue as Alan here, also trying to add a custom attribute on a select element. Matt’s solution also works for me, but looks like this may be a bug that still needs to be fixed