Well, unfortunately, ajax always follows redirects. However, there is a feature that is not supported in all browsers, you can access the responseURL property of the XMLHttpRequest object.

You can try it in the below code snippet. the redirect button sends ajax request to a URL that replies with 1 redirect (it also works if there are multiple redirects). The no redirect button sends ajax request to a URL with no redirects.

As far as I know this method is not supported in IE 11 and older versions of chrome/firefox/opera browsers.

document.getElementById("no-redirect").addEventListener("click", function() {
  testRedirect("https://httpbin.org/get");
});

document.getElementById("redirect").addEventListener("click", function() {
  testRedirect("https://httpbin.org/redirect/1");
});


function testRedirect(url) {
  var xhr = new XMLHttpRequest();
  xhr.onreadystatechange = function(e) {
    if (xhr.status == 200 && xhr.readyState == 4) {
      if (url != xhr.responseURL) {
        alert("redirect detected to: " + xhr.responseURL)
      } else {
        alert("no redirect detected")

      }
    }
  }
  xhr.open("GET", url, true);
  xhr.send();
}

<button id="redirect">
  Redirect
</button>
<button id="no-redirect">
  No Redirect
</button>

This might not be exactly what you're looking for, but maybe it will help you get a similar effect.

If you are in control of what the page http://api.example.com does, you could change the way it reacts when it gets a call via AJAX.

You could include a variable in your AJAX call, marking it as such a call, and if this variable is present, not redirect to an other page, but include the URL it would redirect to, in the answer.

The data returned in the AJAx call could be a hash, in which one key represents the redirect url.

data = {status => 1, redirect => 'http://ap2.example.com', …}

(Sorry if that is not a valid PHP hash)

not sure if I understood it, but just tried something, if it is not what you're looking for please notify me to delete the answer.

here we inject this /#/ in the URL so when clicking on links the browser will have a new segment in the URL which represent the parameter that depending on its value you can determine which page to load using the corresponding AJAX call..

JS/jQuery:

var navLinks = $('#nav a'),
    params = [],
    baseURL = '//localhost/test/js-url-parameters-second';

navLinks.each(function(){
    var oldHREF = $(this).attr('href');
    $(this).attr('href', baseURL +'/#/'+ oldHREF);
});

navLinks.on('click', function(){
    checkURL($(this).attr('href'));
});

function checkURL(docURL){
    // if /#/ found then we have URL parameters
    // grabbing the parameters part of the URL
    if(docURL.indexOf('/#/') > -1){
        docURL = docURL.split('/#/')[1];
        if(docURL != ''){
            // omit the last forward slash if exists
            if(docURL[docURL.length - 1] == '/'){
                docURL = docURL.substring(0, docURL.length - 1);
            }
            console.log(docURL);
            $('#page-type').text(docURL);
        }
    } else {
        console.log('No URL parameters found');
    }
}

HTML:

<div id="nav">
  <a href="home" data-name="Home">Home</a>
  <a href="about" data-name="About">About</a>
  <a href="contact" data-name="Contact">Contact</a>
</div>
<hr>
<div id="container">
  this is the <span id="page-type">Home</span> page
</div>