[TYPO3] JS output in hook class in BE

[misza]

Hello,

I'm a little bit confused with this simple task:

I'm using the processDatamap_afterDatabaseOperations hook to process 
submited data and I'd like to give a feedback to the backend user.
The feedback should be visible both in record editing window and in the list 
view.

The most straightforward way to deal with output is a message in javascript 
alert box.

But the hook class is invoked before the backed form is loaded and 
therefore, due to the headers, it cannot be the simple echo '<script>.....'.

Do you have any ideas how to push the message content ?


Greetz,
Michal