Dans ce billet, Mark Pruett analyse la manière dont les navigateurs réagissent aux appels synchrones : "The problem is that web-browsers are a step backwards as far as multi-threading goes. In Javascript there is no such thing as a new thread, and worse than that, the entire platform (i.e. a browser) runs a single JavaScript thread. If a script in one window goes into a tight loop, or runs some synchronous Ajax then the browser HTML display freezes." Un retour précieux car il est très important de comprendre ce problème lors du développement d'une application Web AJAX.