It will work. Use the following method for appended.
$(document).on('click', 'section.container-A div.elem', function() {
$('section.container-B').append(this) ;
}) ;
Explanation of the problem,
Doing the following,
$("span").click(function(){
An event handler is attached to all span
elements that are currently on the page, while loading the page. You create new elements with every click. They have no handler attached. You can use
$(document).on('click', 'span.class', function(...
That will handle the clicks on the new elements as well.