The done key is the same as the enter key. So you can listen to a keypress event. I'm writing this using jQuery and i use it in coffee script so I'm trying to convert it back to js in my head. Sorry if there is an error.

$('someElem').bind(keypress, function(e){

   // enter key code is 13

   if(e.which === 13){

     console.log(user pressed done);

    } 

})