The walker comes with a bunch of integrated triggers that will fire the event at the right moment.
after loading a page when the DOM is ready
when the element or a child is clicked
after the element has been in viewport for at least 50% for a second
n milliseconds after the load event
as soon as the user scrolls to the specified depth (=n)
on a valid form submission
when leaving the page
trigger is predefined and has to be from the list while the
action can be an arbitrary defined name.