Why are AJAX applications slow? The Founder & CTO of AJAXWorld 2008 East Gold Sponsor Nexaweb, Coach Wei, recently took some time to do some research in the area of AJAX performance issues, and conducted a JavaScript performance study. The three browsers in the study are IE 7, FireFox 2, and Safari 3. Today he published his results.

They can be viewed and read in full here.

The top six AJAX performance issues he pinpoints are:

1.    Array performance on all browsers in general
2.    HTML DOM performance in general
3.    Calculating Computed Box Model and Style
4.    FireFox: “eval”, Object Creation and “in” Operation
5.    “String” Manipulation Performance on IE
6.    Safari: “pop” Operation Performance

Wei then goes on to discuss where the industry could and should go from here.

"Obviously, we would like to see browser vendors take a serious look into the following issues," he writes, "and put them on their roadmap."

The issues are, says Wei:

1. In all major browsers, performance with Array and HTML DOM needs improvement in general.
2. Browsers need to provide API support for Computed Box Model and Style;
3. FireFox needs to improve performance of “eval”, object creation and “in” operation
4. Internet Explorer needs to improve performance in general to be at least on par with other browsers. Beyond that, “String” manipulation on IE needs continued improvements;
5. Safari: “pop” operation performance needs improvement
6. Just-in-time (JIT) compiler: This maybe a bigger task than an incremental fix of some existing features, however, it is worthy of every penny.  JIT will not only fix the String manipulation issue, it will enable JavaScript to truly shine in matching the performance of native applications. The amount of client side logic (aka, JavaScript code) needs to grow in order to accommodate the growth of application complexity, for which JavaScript runtime performance problem can be a major bottleneck.

"But how can we get browser vendors to listen to us?" he asks rhetorically, then answers: