WebKit browser engine aces Acid3 test, stakes claim to No. 1

The latest build scores 100, demonstrates 'smooth animation'

Developers working on WebKit announced late last week that the newest build of the browser engine, which powers both Apple Inc.'s Safari and Google Inc.'s Chrome, has aced all of the requirements of an important Web standards test.

"WebKit is the first browser engine to fully pass Acid3," said developer Maciej Stachowiak in a post to the WebKit blog.

The claim was a follow-up to last March's boast by WebKit developers that the browsing engine had scored 100 out of a possible 100 in the Acid3 test. The test, which was approved last March by the Web Standards Project, is designed to check how closely a browser follows certain standards, particularly specifications for Web 2.0 applications, as well as standards related to the DOM (Document Object Model), CSS2 (Cascading Style Sheets) and SVG (Scalable Vector Graphics).

Last Thursday, however, Stachowiak said that the newest builds also met Acid3's "smooth animation" requirement, something it had failed to do in March, by completing each test in under 33 milliseconds. When a browser finishes each test in that time or less, Acid3 shows the message "No JS [JavaScript] errors and no timing issues" in a pop-up window.

In addition to providing the core engine for Safari, since early this month, WebKit also powers Chrome. Google's browser, however, relies on a version of WebKit older than the one touted by Stachowiak.

Computerworld tested the newest WebKit, Build r36882, in a virtual machine running Windows XP SP3 on an iMac powered by an Intel 2.4-GHz Core 2 Duo processor. Although WebKit scored a perfect 100, it could not complete all tests in the required time in the virtual machine; one test repeatedly failed to meet the 33 millisecond cutoff.

However, when the most recent Mac OS X WebKit, Build r37012, was tested on the same machine, it scored 100 and finished each test under the 0.33ms mark, confirming Stachowiak's claim.

Computerworld's tests also confirmed his statement that no other major browser could match WebKit's Acid3 score. In the Windows XP SP3 virtual machine, all production and preview versions -- the latter indicated by build numbers or status in parenthesis -- scored less than 90 on the test.

Those results were:

  • WebKit, (r36882) -- 100
  • Firefox 3.1, (nightly) -- 89
  • Opera 9.6, (RC1) -- 85
  • Opera 9.52 -- 84
  • Chrome, ( -- 79
  • Safari 3.1.2 -- 75
  • Firefox 3.0.3 -- 71
  • IE8 (Beta 2) -- 21
  • IE7 -- 12

The only other browser maker to stake a claim on Acid3 has been Opera, which said six months ago that a development build of its flagship application had also scored 100.

In related news, Stachowiak recently revealed that a major revamp in WebKit's JavaScript engine, dubbed "SquirrelFish Extreme," was more than twice as fast as its predecessor and over three times faster than the engine included in the current production edition of Safari.

Stachowiak's comments followed similar claims by Mozilla Corp. last month, when the company spelled out massive speed gains from its TraceMonkey project. Mozilla plans to add TraceMonkey to the next edition, Firefox 3.1, due to ship sometime later this year or in early 2009.

According to reports, Apple will integrate new builds of WebKit into Safari 4, which has been seeded to some developers for testing and is expected to publicly launch with Mac OS X 10.6, a.k.a. "Snow Leopard," the next version of the company's operating system. Snow Leopard, which Apple has said will ship sometime next year, will focus on stability and performance improvements, rather than on adding more features to the operating system.

The newest WebKit build is the only browser engine to score a perfect 100 on Acid3
The newest WebKit build is the only browser engine to score a perfect 100 on Acid3. Second is Mozilla's upcoming Firefox 3.1.

Copyright © 2008 IDG Communications, Inc.

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