Can JQuery listen to AJAX calls from other javascript?

Question

I need to build a feature into a shopping cart that uses AJAX to retrieve an updated copy of the template from the server when something changes (e.g. a product is removed). I cannot modify the server side code, or the JavaScript that makes the shopping cart work in the first place. (Not ideal I know, but that's how it is)

What I want to do is run my own JavaScript every time the cart updates. I want to know if it is possible to listen for AJAX calls, and run my code every time one is made.

Answer 1

To follow all AJAX calls on an HTML doc, you can overwrite the XMLHttpRequest prototype. This way, you can watch for actions on methods of XMLHttpRequest objects.

Here's a small sample code :

var open = window.XMLHttpRequest.prototype.open,     send = window.XMLHttpRequest.prototype.send,     onReadyStateChange;  function openReplacement(method, url, async, user, password) {     var syncMode = async !== false ? 'async' : 'sync';     console.warn(         'Preparing ' +         syncMode +         ' HTTP request : ' +         method +         ' ' +         url     );     return open.apply(this, arguments); }  function sendReplacement(data) {     console.warn('Sending HTTP request data : ', data);      if(this.onreadystatechange) {         this._onreadystatechange = this.onreadystatechange;     }     this.onreadystatechange = onReadyStateChangeReplacement;      return send.apply(this, arguments); }  function onReadyStateChangeReplacement() {     console.warn('HTTP request ready state changed : ' + this.readyState);     if(this._onreadystatechange) {         return this._onreadystatechange.apply(this, arguments);     } }  window.XMLHttpRequest.prototype.open = openReplacement; window.XMLHttpRequest.prototype.send = sendReplacement; 

With this sample, for every AJAX call you'll have a warning in the JavaScript console.

It's not jQuery script, but you can use jQuery inside as you want.

This solution probably won't work on IE 6 or older, but it works in FF, IE7+, Chrome, Opera, Safari...