This page allows you to test all of the API endpoints that the Tasker WebUI has to offer.
You can use these APIs to build your own Edit Task screens.
You can use this page as an example. To use it, just download the html file to your device and open it in a browser. You can take a look at its source code to see how it works.
IMPORTANT: because of security reasons the example page above won't work directly on a public URL. You have to download it to a device and run it locally from your file system.