You would need to allow the user in question to reload the app, either using a Reload Button object or using Automation. You would then have the user input the dates into variables (rather than field selections) and you can use those variables in your script. You'd also need to make sure the script can run and return the expected results based on a schedule, presumably, to give the user a starting point. This will also fail to work if multiple people are using the app, as each one will reload and override the previous data (or attempt to reload while the app is already reloading, etc).
I would not advise using this approach. I would suggest either using ODAG, or fetching the entire dataset and adding the date filter as a regular filter or with set analysis.
