How to add thousand separator to a variable in an MRVS in the modal dialog shown when clicking 'add'

[smicloud]

I would like to add a thousand separator to a variable in the modal dialog opened when clicking 'add' to an MRVS in a record producer. 

I can find no way to do this. I think it is not possible but I hope to be proven wrong. 

On a variable in the record producer form I can do this using onChange catalog client script on the variable. Unfortunately this option is not available in the model dialog of the MRVS. 

I was thinking perhaps a custom variable using widget can be used but I can't figure out how that would be work in that case. 

Any ideas?

[smicloud]

The questions was related to the modal dialog, nothing else. 

Outside MRVS it is not problem, you could use an onChange catalog client script to alter the format of whatever the user inputs. We are already doing this for some fields.