Bind on(keyup) to dynamic elements in jQuery (Twitter Bootstrap + typehead)

For on() to be able to delegate you have to call it on a static element that you know is always going to be there and then you pass the dynamic element like:

$('#static-parent').on('keyup', '#aDropdownID', function(ev){
 // stuff happens
});

If you don't have a static parent element, then you can always use body.

This works for me:

$(document).on('keyup', '#YourInputFieldId', function () {
    //stuff happens
});