Written by memory, not tested, but can be used as basic draft (if this is
what you ask about):
<style>.popup{display: none;/* some other styles */}</style><ahref="#"data-popup="#my-popup">Show form</a><divclass="popup"id="my-popup">{controlpopupForm}</div><script>$("[data-popup]").on("click",function(e){
e.preventDefault();$($(this).data("popup")).show();});</script>