messin with firefox context menu

foo.js

Cu.import('resource://gre/modules/Console.jsm');

// get a pointer to the context menu
// TODO: seems to be per-window. how to iterate and attach to all windows? :-(
menu = document.getElementById("contentAreaContextMenu");

// create a hidden menu item
xuldoc = menu.ownerDocument;
item = xuldoc.createElement('menuitem');
item.setAttribute('id', 'minvid-item');
item.setAttribute('label', 'console.log selected URL');
// TODO: wait on toggling visibility for now
// item.setAttribute('hidden', true);
item.setAttribute('oncommand', () => {
  console.log('the link URL is: ', gContextMenu.linkURL);
});

// append the item
menu.appendChild(item);

menu.addEventListener('popupshowing', () => {
/*  if (gContextMenu.linkURL) {
    item.removeAttribute('hidden');
  } else {
    item.setAttribute('hidden', true);
  }
*/
  
  // TODO: doesn't work...
  console.log('gContextMenu.linkURL is: ', gContextMenu.linkURL);
})