Fires after the user clicks the Print button in the Print dialog box before content is assembled for the printer (onbeforeprint) and after the data has been sent to the printer (onafterprint). You can use these events to trigger functions that modify a style sheet or other content rendering of a page (so that a potentially different-looking page reaches the printer) and then restore the page for viewing on the screen. This technique can work in lieu of style sheet media settings.