Hello Michael/
thank you for your help.
I followed your advices for the point 1. and I noticed something interesting
The clickable function depends on the browser
The activation of the filter plugin by click does not work under Firefox, Opera and Chrome
But it succesfully works under Internet Explorer
It’s possible to do something in order to activate the box under all common browser ?
My webpage is
http://www.swisskarst.ch/index.php/en/results/documentation/by-canton
Thank
Arnauld