Hi Sugura,
Probably the HTML/JavaScript Snippet widget can help you to run a JS (and register an event listener) during page loading. It is worth a shot!
Best,
Istvan
Hi Suguru,
There is a close page Action that can be modelled in a Nanoflow (Client side). https://docs.mendix.com/refguide/nanoflows/
Adding an addEventListener is not possible.
You can create custom Javascript Actions: https://docs.mendix.com/howto/extensibility/write-javascript-actions/
You can interact with the Client API from these Javascript Actions: https://docs.mendix.com/howto/extensibility/write-javascript-actions/
Go Make It