<!doctype html> <html lang="en"> <head> <script src="http://play.workadventure.localhost/iframe_api.js"></script> </head> <body> <div> <label for="show/hideLayer">Crysal Layer : </label><input type="checkbox" id="show/hideLayer" name="visible" value="show" checked> </div> <script> document.getElementById('show/hideLayer').onclick = () => { if (document.getElementById('show/hideLayer').checked) { WA.room.showLayer('crystal'); } else { WA.room.hideLayer('crystal'); } } </script> </body> </html>