Provides the ablity to run functions before and after a print request.
Initiate OnPrint
var OnPrint = require('on-print')
, printListener = new OnPrint()
Add a function to run before print
printListener.on('before', fn)
Add a function to run after print
printListener.on('after', fn)
Start watching for print events
printListener.start()
IE 5+, Firefox 6+, Chrome 9+, and Safari 5.1+ (not Opera)
BSD
Matthew Harrison-Jones, Ben Gourley
Adapted from: http://tjvantoll.com/2012/06/15/detecting-print-requests-with-javascript/