javascript with dropdown lists

good morning everyone,

I'm playing around today with JavaScript code to add an "item" to my dropdown list if a certain condition is met.

The code seams to work if preview mode, but when I go back to designer mode and preview again, the item isn't really saved as an item of that dropdown list object, what am I doing wrong here?

Here is code:

If (d2 > tmpAprildate){

   xfa.host.messageBox("its greater then April 1st.");

   //add to dropdown list

   DropDownList1.addItem(curfy);

}else{

//do nothing

}

so I can see it being added to my drop list just by looking into it. But if I leave and come back, it needs to be added again as it didn't really save it

Thank you very much for your help again with this

Patrick