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.
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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.
I am not sure exactly what kind of prepopulated grids you are looking for, but you may want to try using our Matrix form field found under Survey Tools:
If you want to send out the form to your users with values already prepopulated, you can refer to our guide on Prepopulating fields to your JotForm via URL parameters.
For instance, if you were looking to prepopulate values in the matrix of your form Employee of the Month Voting Form, you could use form URLs such as this:
It would result in the fields of the grid/matrix being prepopulated:
If you were looking for something else, please provide a little more information about what you are trying to achieve, and we will be happy to help.