index.php
You do not need to display the html code in go.php after you finish processing the POST data
Try this
$(document).ready(function() {
$("#verifica").click(function(){
$("#risultati").html("Please wait...");
$.ajax({
type: "POST",
url: "go.php",
data: $("#ciao").serialize(),
//dataType: "html",
success: function(msg)
{
$("#risultati").html(msg);
$("#zio").focus();
},
error: function()
{
$("#risultati").html("An error occurred.");
}
});
});
});