Pass values to pop up form after success of previous form

Pass values to pop up form after success of previous form

Hello, I have a form that pops up after the success of another form. How do I pass the values to the pop up form from the previous form? Ex: In the main form, I enter 1/1/2017 in the date field. After submitting the form, a pop up form appears and in the date field of the pop up form the value = 1/1/2017.