How can I generate checkbox options based on textbox input

For example: if firstname starts with M then have test1, test2, and test3 as options for a checkbox field   

Hi,

You can't dynamically generate the check box, but you can have them setup then show them based on the user input.

Here's an example form that I made: http://form.jotformpro.com/form/52245534003949.

1. Here I added First Name and Last Name as separate text boxes, I then setup a 2 check boxes with fixed options. I have "Check box (M)" for first name starting with "M" then "Check box (S)" if it starts with "S".

2. I then use conditional logic to dynamically show those check boxes.

3. Here's how I setup my rule and action.

4. Just repeat the same process for the letter "S".

Note: No need to set the check boxes to hidden, when the rule is not meant using the "Show" action, it automatically hide the field.

I hope that helps. Do let us know if you need more information on this.