Have you had a look at the code from mnmlst theme, Simple Ajax tutorial for Kirby?? This is the ajax code that does the page loading:
var loading;
$(document).ready(function(){
$('a.internal').click(function(e){
e.preventDefault();
loadLink($(this)[0].href, true);
});
window.history.replaceState({'data' : window.location.href});
window.addEventListener('popstate', function(event) {
loadLink(event.state.data, false);
});
$('section').hide();
$('section').fadeIn(500);
var done = true;
});
function loadLink(urlload, newS){
loading = true;
console.log(urlload);
NProgress.start();
$("html, body").animate({ scrollTop: 0 }, 500);
$('section').fadeOut(500);
$.ajax({
url : urlload,
dataType : 'html'
}).done(function(data){
loading = false;
NProgress.done();
if(newS) window.history.pushState({'data': urlload}, $(data).title, urlload);
setTimeout(function(){
var newDoc = document.open("text/html", "replace");
newDoc.write(data);
newDoc.close();
}, 500);
});
}
Edit: If you use my code from the previous answer, you can just remove all content before you load new content.