[ucjs]默认添加书签到上次使用的文件夹

(function addBookmarkInLastUsedFolder() {
  PlacesUtils.__defineGetter__("lastUsedFolderId", function() {
    var annosvc = this.annotations;
    return annosvc.getItemsWithAnnotation(LAST_USED_ANNO)
                  .map(function(aId) [aId, annosvc.getItemAnnotation(aId, LAST_USED_ANNO)])
                  .reduce(function(aFolder, bFolder) aFolder[1] > bFolder[1] ? aFolder : bFolder, [0, 0])[0];
  });
  
  eval("PlacesCommandHook.bookmarkPage = " + PlacesCommandHook.bookmarkPage.toString()
    .replace("PlacesUtils.unfiledBookmarksFolderId", "(PlacesUtils.lastUsedFolderId || $&)")
  );
})();

document.getElementById("Browser:AddBookmarkAs").setAttribute("oncommand", "PlacesCommandHook.bookmarkCurrentPage(true, PlacesUtils.lastUsedFolderId || PlacesUtils.bookmarksMenuFolderId);");