Datepicker only months and year

[babel]

Formbuilder 1.0.2 is working fine, except in the datepicker. If I remove day in dateformat and the day in the date component, the required field is not working. Even if customers have filled a month and year, they get a message that the datefield is not filled. So the question is how can I get a working datefield with only months and year?
I'm using cms ms 2.2.12

[DIGI3]

When I've done this I just hide the day field with css/js. Give it a default value so it passes validation, but the visitor doesn't see it.

[babel]

Thanks Digi3. Your solution works.