Is there any shortcut to comment out JavaScript code in Notes? I know the shortcut for Xpage is ctrl+shift+c
I do not know your version of Domino Designer, so I can only provide a genearal answer to JavaScript comments.
If you only have one line you want to comment, just use // at the beginning of that line.
If you want to comment multiple lines, start the comment with /* and end it with */.
Maybe you can find such a shortcut under Preferences --> General --> Keys (if your Domino Designer has that entry).