Yes of course,
these possibilities are also available in the simple editor of Wix, but I want this animation to be performed at each passage of the scroll, even during the same session.
These effects shown are achieved only once, during the first passage if I’m not mistaken
And it is this mechanism that the Jscode that I wanted to implement is supposed to be made… 
With these properties, I can just show / hide the elements at the end of their initial animation.
What I want to take as a trigger is if it is visible or not on the page, on the screen depending on the position of the scroll bar:
If it is visible: show,
If it is not visible: hide
At each passage of the scroll bar