Defold-Input contains a number of different Lua modules and scripts to simplify input related operations such as gestures detection, user configurable key bindings, input state handling and dragging/clicking game objects.
You can use the extension in your own project by adding this project as a Defold library dependency. Open your game.project file and in the dependencies field under project add:
https://github.com/britzl/defold-input/archive/master.zip
Or point to the ZIP file of a specific release.
You can try an HTML5 demo of Defold-Input here: https://britzl.github.io/Defold-Input/
For a complete and easily skinnable UI system that supports buttons, checkboxes, input fields and lists please take a look at Gooey.