Chicago (IL) - Most of today’s web sites and web applications are built using theJavaScript scripting language. Some may say that a trend towards thefine-tuning of JavaScript interpreters in modern browsers was just amatter of time since any such optimization translates into performancegains. Mozilla recently launched the browser speed race with Firefox 3,which delivers more speed than any other previous Firefox version.Apple answered with Safari 4, claiming the browser’s JavaScript enginehas been accelerated by 53%. Welcome to the browser speed race.
Safari 4 has just been seeded to the developers at Apple’s developer conference. The manufacturer claims that the software has a 53% faster JavaScript engine than the preceding and current version 3.1 (based on the SunSpider JavaScript Performance test conducted on iMac with an Intel Core 2 Duo processor at 2.8 GHz, with 2 GB of RAM and running under Mac OS X Snow Leopard.) Although Firefox 3 RC3 was the first to deliver significant JavaScript performance improvement, Apple apparently is exceeding those gains with Safari 4.
Apple uses a new and improved JavaScript interpreter code-named SquirrelFish, which is provided on an open-source basis from the WebKit project, the same organization that makes the open-source engine used by Safari to render web pages. According to the WebKit project, the SquirrelFish engine is 1.6 times faster than the JavaScript engine in Safari 3.1.
SquirrelFish does its magic by turning JavaScript script into so-called bytecodes, an optimized code much more suitable for run-time execution than natural language-based JavaScript commands, which are longer and more complicated to interpret - and therefore are slower.
Why JavaScript performance matters
Most today’s web applications and web 2.0 sites rely on the JavaScript scripting language originally created by current Mozilla CTO Brendan Eich while he was employed by Netscape. JavaScript acts as glue that connects a user interface rendered in a web browser with a database and programming logic running in a web server. The browser’s JavaScript engine is solely responsible for interpreting and executing JavaScript commands embedded in HTML code. As a result, a browser’s JavaScript engine performance is directly related to the performance and responsiveness of a web application, contributing to an improved user experience.
The fact that many applications grow in size and become more bloated with each release means that a browser that can run web applications faster and make user interfaces more responsive on any computer is actually a big deal. You don’t have to have any specific market forecasting talent to predict that this trend may be impacting browser market shares: Speed can directly translate into more usability for most of us. Clearly, JavaScript handling is on its way to become a powerful weapon in the browser market.
SpiderMonkey, SquirrelFish, Tamarin and more
Mozilla was the first to introduce significant speed gains with Firefox 3 beta 5 (the final version is expected to ship by mid-June). Firefox has its Gecko engine to render web pages, which is generally considered to be slightly slower than Safari’s WebKit - which is largely responsible for the "fastest browser in the world" status Safari enjoys. Firefox’ JavaScript implementation is based on Mozilla’s own and decade old SpiderMonkey technology, which many considered to be the fastest JavaScript interpreter until SquirrelFish came out.
Although in beta, Firefox 3 scored with many reviewers who are praising the browser’s performance improvements, with WSJ’s Walt Mossberg declaring the browser a "winner." But now that the SquirrelFish/Safari combination appears to be offsetting the speed gains in Firefox 3 and may set a new benchmark, we can expect more direct competition between Mozilla and Apple. Mozilla has plans to expand SpiderMonkey with Adobe’s JavaScript engine called Tamarin, included in Flash 9, which has a so-called "tracing" feature designed to enable faster code execution. However, the SunSpider JavaScript benchmark claims that SquirrelFish is at least 1.9 times faster than Tamarin.
Mozilla plans to wedge Tamarin into Firefox and match the API’s of both technologies "There are areas in which SpiderMonkey is faster than Tamarin and areas where it’s not. We’re looking to build hybrids that are best-of-breed for both worlds and we’re going to pull those into the Firefox release when ready," Mozilla co-founder Mike Shaver recently said.
Can IE8 compete?
The big variable in this game is Microsoft’s Internet Explorer 8, currently in beta 1 phase. IE8 is expected to deliver speed gains in JavaScript performance as well. However, Microsoft is facing a tough task. The fact that the software giant is often criticized for delivering bloated and inefficient software certainly doesn’t help. In our tests, the first beta of IE8 shows no noticeable speed gains in running web applications.
Quite the opposite is the case, actually. Websites and web applications run noticeably slower than in IE7. The whole browsing experience generally appears to be less responsive. Of course, IE8 is in an early development stage and you can bet Microsoft is going to tweak its performance. The only problem is that the software giant will have to work to raise the stakes in the browser race. If IE8 under-delivers, the market could respond with further market share erosion for IE. It is evident now that JavaScript engine performance has become a key metric in the newest race for the title of fastest browser.
The battle ahead is nicely summed by Mozilla co-founder Mike Shaver who said the following: "They [Apple] have dropped SquirrelFish in now and got a big speed up there. We’ve got more coming on our side. You’ll see this leapfrog pattern over and over. We’re not going to let anybody slack on that and the other browser vendors need to keep up, too."
According to Net Applications, Firefox 3 captured almost one fifth (18.41%) of the browser market in May, followed by Safari 3.1 which hit 6.25%. Microsoft’s Internet Explorer continues on its pace of a slow but steady decline, ending up at 73.75% in May. Microsoft has scheduled second beta of IE8 for an August release, with a generally expected final release in the fourth quarter of this year.
