1> copy to your Emeditor Macros directory.
2> Macros -> Customize -> New -> CMT.js
3> Enjoy the comment fun!

feature:
1> Multiline support.
2> SingleLine with commented date.
3> CSS, HTML, Javascript, C#, C-like, Java comment are supported;

Suggestion:
Define the shortcut for keybord:
Properties for All Configurations -> Keybord -> Catagory -> My Macros ->CMT.js -> Press new ShortcutKey -> Ctrl + / -> Assign