Detect when a popup has closed on the page using polling. Kudos to http://stackoverflow.com/questions/3291712/is-it-possible-to-open-a-popup-with-javascript-and-then-detect-when-the-user-clo for the idea. Polling isn't neat, but there's not a neater way here.

whenPopupClosed.js

var whenPopupClosed = function (popupWindow, cb) {
  var pollTimer = window.setInterval(function() {
    if (popupWindow.closed !== false) { // !== is required for compatibility with Opera
      window.clearInterval(pollTimer);
      cb();
    }
  }, 200);
};