Browsers did not anticipate the rapid surge of Ajax applications and they are increasingly slow to render Ajax-ed websites. They used to be snappy and responsive, now it’s quite easy to find yourself typing in a text area at the amazing speed of 1 character per second. A new quad-core processor or the latest version of your favorite OS can do nothing to change this.

For Mozilla-based browsers the problem is called SpiderMonkey, the internal Javascript engine.

Thankfully last November Adobe announced that it has contributed source code from the ActionScript Virtual Machine to the Mozilla Foundation as project Tamarin. The goal is to implement a high-performance, open source implementation of the ECMAScript 4 (ES4) language, more generally known as “JavaScript 2”.

This means that Tamarin code will be integrated into SpiderMonkey and hopefully this will make future versions of Firefox based on Mozilla Application Framework 2 significantly faster at executing AJAX-enabled web applications. Unfortunately this won’t happen any time soon: Firefox 4 is due on late 2008. Recently a first Reference Implementation of ES4 has been released, and as Mitchell Baker says:

The Reference Implementation is an early release, allowing the power of many eyes and many brains to understand and participate in the development of JavaScript 2. […] Making the Reference Implementation public now encourages review, evaluation and comment. This brings the benefits of greater understanding, problem finding and problem solving that we’ve become familiar with in the open source world.

Needless to say that Clipperz is soon going to run tests and benchmarks of its online password manager on Tamarin!

(The real cute Tamarin …)