Maciej Stachowiak of the WebKit team has announced that the browser engine behind Safari is the first to fully pass the Acid3 test, including the test's condition of smooth animation rendering.

Acid3 is a test page from the Web Standards Project that scores how well a rendering engine follows defined web standards, particularly DOM and JavaScript. The test provided a metric for standards compliance that has resulted in rapid advancement among various rendering engines as each works to earn the top score.

In March, both Safari's WebKit and Opera's Presto announced earning a 100% score in developer builds of their browser. In addition to the numbered score, the test also requires the browser render a test page with pixel perfect accuracy using its default settings and that it render a smooth test animation.

Today, the development build of WebKit passed that last hurdle, which Stachowiak reported was due to "recent speedups in JavaScript, DOM and rendering."

Actual shipping builds of the world's various web browsers haven't yet reached 100%. According to figures in Wikipedia, the latest Safari 3.1.2 has a score of 75, while Firefox 3.0.2 has reached 71, Opera 9.52 has reached 84, and Internet Explorer 7 is at 14.

In internal builds, the Safari 4.0 Developer Preview has reached 100, while the latest build of Firefox Gecko engine has reached 87, the latest build of Opera earns 99, Google's new Chrome beta has reached 79, and the Internet Explorer 8 Beta 2 scores 21.