Does deckjs - split works !

I make a test of split option of deckjs but that does not work

= Presentation Title
Presenter Name
:backend: deckjs
:split:

== This Slide is Split

This Slide will act like

<<<

three individual slides with the same title

<<<

once the document is rendered.

In this case, just 2 slides are displayed in my browser (MyProject/test.html#title-slide, MyProject/test.html#_this_slide_is_split) and not one plus 3.

Remark : deck.split.js has been installed (MyProject/deck.js/extensions/split/deck.split.js)