Performing cleanups

When your behavior modifies things outside itself (eg, binds events to the document element), you might want to clean up when the behavior is removed. Just pass a 2nd function to onmount().

In this example below, behaviors are checked once dialog boxes are opened and closed ($.onmount()). When it’s called after closing, it will see that the old .js-sticky element is not part of the document anymore, and its exit callback will be called.

$.onmount('.js-sticky', function () {
  $(document).on('scroll.sticky', function () {
    // do stuff
}, function () {

$(function () { $.onmount() })
$(document).on('', function () { $.onmount() })