Microsoft hit another milestone in the release schedule of MSIE 9 this week with the fourth platform preview of IE9. This release includes over 1300 bug fixes and the inclusion of a new JavaScript engine which is said to increase the browser’s performance by leaps and bounds.
With the integration of the new JavaScript engine, codenamed Chakra, the performance of major websites is considerably improved, as the browser shares a DOM (Document Object Model) between the browser and the script engine, which is based on ECMAScript5.
The biggest test of the new browser is the fabled Acid3 Test. With each release, IE has improved its score. In March it scored 55, in May it was 68, and in June it increased again to 83. With this release, IE9 topped out at 95, which is impressive for any browser that is currently available.