I may have answered my own question by letting the page finish to load.
For anyone on the same track, I used this answer on stack
<http://stackoverflow.com/a/12897970/1078583>:
window.addEventListener('load', function() {
// your code here
}, false);
--
You received this message because you are subscribed to the Google Groups
"greasemonkey-users" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To post to this group, send email to [email protected].
Visit this group at https://groups.google.com/group/greasemonkey-users.
For more options, visit https://groups.google.com/d/optout.
