Change page in the middle of Ajax request

Question

What happens if I send some ajax request, and immediately change the page (say follow some link) before the request returns? I mean I suppose the XHR object sends a request

Answer 1

The trick is to check the response headers in the XMLHttpRequest object. If there are no response headers (null or empty string, depending on the browser), the server did not respond yet. That means the user aborted.

$.ajax({
    url: "url-to-go-here",
    success: function() {
    },
    error: function(xhr, textStatus, errorThrown) {
        if(!isUserAborted(xhr)) {
            console.log("Ajax Error")
        }
    }
});

function isUserAborted(xhr) {
  return !xhr.getAllResponseHeaders();
}

Source