what is the event to handle before leaving the page?

Hello All,

I am using splitApp. I have a scenario where user can edit few fields in one of the "Detail" page. When user clicks some item in master page, before changing the detail page I want to show a popup to user if changes should be saved.

Is there an event where I get to know any detail page navigation? or some event to handle before leaving the page.

Thanks,

Rashmi