This is one of the crazier workarounds that I have implemented. I was working on a web page that embeds third-party widgets. The widgets are drawn in the page document - they do not get their own frames. And sometimes the widgets are redrawn after page load. We had a problem with one widget invoking document.write(). In case you are not familiar with it, if that method is called while the page is rendering it inserts content into the DOM immediately after the script tag in which the call is made. But if document.write() is called after page rendering is complete it erases the entire DOM. When this widget was redrawn after page load it would kill the whole page. …

Promises, also know as deferreds or futures, are a wonderful abstraction for manipulating asynchronous actions. Dojo has had Deferreds for some time. jQuery introduced its own Deferreds in version 1.5 based on the CommonJS Promises/A specification. I'm going to show you some recipes for working with jQuery Deferreds. Use these techniques to turn callback-based spaghetti code into elegant declarative code.