How to check if HTTP requests are open in browser?

Question

Is there an easy way to detect if an XMLHttpRequest is active in the browser window? Or how many are active? ie. Is there a way to detect if there are any AJAX calls active in my browser window?

Extension of question: Using javascript is there a way I can see if any XMLHttpRequests are open? Such as "window.XMLisActive()" or something like that?

Solution: Ended up writing a wrapper for XMLHttpRequest: gist here

Answer 1

There is not a way to detect an open connection from JS unless you write a wrapper for XmlHttpRequest (or monkey patch it) that keeps track of opened connections.

Here's kidcapital's monkey patch, not sure if it's perfect, but it's a good start

  (function() {
    var oldOpen = XMLHttpRequest.prototype.open;
    window.openHTTPs = 0;
    XMLHttpRequest.prototype.open = function(method, url, async, user, pass) {
      window.openHTTPs++;
      this.addEventListener("readystatechange", function() {
          if(this.readyState == 4) {
            window.openHTTPs--;
          }
        }, false);
      oldOpen.call(this, method, url, async, user, pass);
    }
  })();

Note

This does not handle fetch or websockets but you could do something similar in those cases.

Answer 2

You can use FireBug for that.

Answer 3

By using jQuery, you can keep track if there are open requests with the global event handlers: .ajaxStart() and .ajaxComplete()

A global variable set on ajaxStart and reset on ajaxComplete should do the job.