Popup before user navigate away from current view via portal link

Hello all,

I am trying to provide the popup to the user saying "Data might be lost".

I have portal with create , change and display link and right side webdynpro for abap component is embedded using Iview.

Let's say user is in Change mode and changes something in the webdynpro view now when user click on the Display link -->> in the portal.

I want to display the popup.

I have tried provided WDDOEXIT method ( which only i feel getting triggered ) but its not right place to put the popup .

Waiting for the suggestion.

Thanks

~Raj