what is the best way to activity chain a subprocess/task after an exception flow

When you say: "but it won't work." what do you mean?

it won't activity chain to the next task. My scenario is a user will reserve a slot (update db) after 30mins. while the form is still open,and status is still <>"confirm",it should trigger an exception flow and start subprocess (cancel update in db) and return to the same form with a new message that the reservation has been auto-cancelled.It's like updating db and refreshing the form values when certain conditions are met

Oh I see, well...but how were you enabling activity chaining in an exception flow? exception flows cannot be activity chained.

yes i know,but i saw suggestions in a thread that you can achieve it by connecting the exception flow to an empty script task and activity chained it to the next task, but this does not work when i tried it. What's the best way for the user to see the updated values from the db while their form is currently open so users will be notified on the form the available slots and/or that their reservation has been auto-cancelled by the system.

i also tried using timer event,but still it won't update "left-opened form" values.what i want to achieve if possible. while the form is currently open,it would search db for updated values and show it to that same form without having to close it.

it's like auto-submit form when the exception flow was triggered.

Why not auto-submit after 30 mins? As this is done using JS it works only in the browser.

I have the same scenario. I am auto-submitting the form after 30 mins using setTimeOut function. If the user closes the browser before 30 mins, what happens to the timer? Is there any other way we can achieve this functionality?

The setTimeOut function is JavaScript meaning it's client side code. If you close the browser the task will not submit.

In that case you should be able to use exception flows: Autosubmit after 30 mns with JS will present the next form but if they close it then the exception flow will skip that task too.