Full ECMAScript (JavaScript) 5.1 support

September 13th, 2011

This build adds full support for the ECMAScript (JavaScript) 5.1 specification.

At time of writing the test262 test suite is reporting one error from a total of 10927 tests on the Windows and Mac platforms. As a comparison, Opera 11.51 on Windows has 3865 failures. See the known issues below for information on Linux.

Keep in mind that the test262 test suite is undergoing active development and far from complete. Even a perfect score in the current version of the test suite does not guarantee perfect ES 5.1 conformance. Results may also vary depending on when the test was run, as tests could be added, removed, fixed or otherwise altered at any time. Case in point: The only test that fails in this snapshot, S11.1.1_A2, is invalid.

That leaves Opera with a "perfect score" on Windows, Mac and 64-bit Linux in the current test262, while still keeping the unstable nature of the test suite in mind.

In addition to full ES 5.1 support, we have added a native implementation of ECMAScript typed arrays. This offers increased performance when dealing with things like binary data, and will be noticeable when, for example, using emulators or playing games using Canvas.

This build also adds support for <video muted> to mute HTML5 videos by default, and Linux users can enjoy GTK+3 support which means that Opera looks native again on Gnome 3 based systems (like Fedora).


  • CORE-28638 Implement full support for new ECMAScript 5 features
  • CORE-38784 Native implementation of ECMAScript typed arrays for increased performance
  • CORE-40275 Implement <video muted>
  • DSK-343260 Support GTK+3 on Linux
  • CORE-33418 Update to the Unicode 6.0.0 specification

Known issues

  • Two valid tests in the test262 test suite fail on 32-bit Linux (works on 64-bit systems)

WARNING: This is a development snapshot: It contains the latest changes, but may also have severe known issues, including crashes, and data loss situations. In fact, it may not work at all.