Can't set value of Selectivity instance

[vince83110]

I use last version of Selectivity.

I just want to set the value of a multiple Select, here is my code :

$('#informations_InvitationsRendezVous').selectivity({
        multiple: !0,
    });

document.getElementById('informations_InvitationsRendezVous').value = 2;

$('#informations_InvitationsRendezVous').selectivity('value', [1, 2]);
$('#informations_InvitationsRendezVous').selectivity('open');

Here is the fiddle : https://jsfiddle.net/4g8m5dnx/

It doesn't set the value, it does nothing. I tried many ways.

How can I simply set the value(s) ?
Thanks