Thank you for your post.
From page 32 of the FileMaker WebDirect Guide, it states:
"Only the Tab key is supported for navigating between fields or objects in FileMaker WebDirect."
I recommend that you enter this suggestion into our Feature Requests web form at:
The entry into this web form populate a database that is hosted by Product Management and Development. Each entry is discussed and considered for a future release. Although I could copy your post and past it into the web form, there are a couple of questions on the form that only you can answer.
Hmmm, wonder if you could use the OnObjectKeystroke script trigger to perform a script that moves the cursor to the next field when the Enter or Return key is pressed...
I think this might work, but you would be doing all of the processing on the server, so performance could be very poor. For the moment I am having the client train staff to hit the tab key.
"FileMaker WebDirect does not support the OnLayoutKeystroke and OnObjectKeystroke script triggers."
FileMaker 13 WebDirect Guide page 21
OnObjectModify might work but as beherbac pointed out this might lead to poor performance.