What is JotForm?
JotForm is a free online form builder which helps you create online forms without writing a single line of code. No sign-up required.
At JotForm, we want to make sure that you’re getting the online form builder help that you need. Our friendly customer support team is available 24/7.
We believe that if one user has a question, there could be more users who may have the same question. This is why many of our support forum threads are public and available to be searched and viewed. If you’d like help immediately, feel free to search for a similar question, or submit your question or concern.
Unfortunately, it is not possible, you could try to just add manually text boxes or drop down to recreate a date field, here's an example:
You can move them to the same line by following this guide on how to position fields: http://www.jotform.com/help/90-Form-Field-Positioning.
Here's my sample form: http://form.jotformpro.com/form/51045054403947?
We can further adjust the width and the padding by using custom CSS codes.
I hope that helps.