Essentials of Javascript - Cultural View

JavaScript engine 45
Performance evolution
"..previously behind-the-scenes programming technology called JavaScript is getting new visibility .. "
—-CNET [2]
A typical major browser has a graphical engine and an independent JavaScript engine, which allows for easier
testing, reimplementation or usage in other projects. For example Carakan is used with Presto, Nitro with WebKit,
SpiderMonkey with Gecko, KJS with KHTML, Rhino by default doesn't have any layout engine. Other
combinations are sometimes possible, for example, V8 with WebKit in Google Chrome. The JavaScript engine gives
developers access to functionality (networking, DOM handling, external events, HTML5 video, canvas and storage)
needed to control the web browser.
Sunspider is a JavaScript benchmark utility for measuring the performance of JavaScript engines in more than a
dozen of tests, each concentrating on different part of JavaScript language. Sunspider doesn't use for benchmarking
any features beyond this needed to test pure computations (no HTML, no CSS, no networking).
The JavaScript engine race: 2008 and 2009
There has since been a race by browser developers to develop even faster JavaScript engines. In 2008, Google
Chrome was praised for its JavaScript performance, but other browsers soon received new JavaScript engines which
were faster. Later, Google Chrome won in the races of better performance. Chrome's strength is its application
performance and JavaScript processing speed, both of which were independently verified by multiple websites to be
the fastest amongst the major browsers of its time. [3] [4] [5] With the advent of WebKit's Squirrelfish Extreme and
Mozilla's TraceMonkey JavaScript virtual machines, Chrome's JavaScript execution performance has been found to
be slower. [6] [7] [8] [9] Google responded with the Danish developed V8 (JavaScript engine) which boosted JS
performance in Google Chrome 2.
On June 2, 2008 the WebKit development team announced SquirrelFish [10] — a then new JavaScript engine that
vastly improves Safari's speed at interpreting scripts. [11] The engine was one of the new features in Safari 4, released
for developers on June 11, 2008; the final JavaScript engine was called Nitro.
2009
In January 2009 the engine then known as SquirrelFish Extreme (SFX) was enabled for Mac OS X on x86-64
architectures as it passes all tests on that platform by Apple Corp.. [12] Released June 30, 2009 Firefox 3.5 includes
the optimization technique which offered "performance improvements ranging between 20 and 40 times faster"
compared to Firefox 3 in some cases [13]
The JavaScript engine race: 2010
In early 2010 the Norwegian Opera browser replaced the aging Futhark with the faster Carakan, which was 2.5 times
faster in early testing [2] Others in the race at this time include Apple's Safari's Nitro (the engine formerly known as
SquirrelFish), and Firefox's new JaegerMonkey (a "cross-child of Nitro with the older TraceMonkey Engine"). [1]
Microsoft lagged behind, lacking a dedicated JavaScript engine and being the slowest of the major browsers,
although by mid-2010 they held out the carrot of Chakra in then unreleased Internet Explorer 9. [1] JägerMonkey
began testing in the publicly released Firefox 4.0 beta in the Summer of 2010. [14] Safari 5, also released in summer
2010, featured 30 percent faster JavaScript performance then Safari 4 (using the Nitro engine). [15]