New in JavaScript 1.8.1

JavaScript 1.8.1 is a modest update syntactically to JavaScript; the main change in this release is the addition of the Tracemonkey just-in-time compiler, which improves performance.

There is a notable API change removing the branch callback and replacing the operation callback detailed in this newsgroup posting.

Language additions

Object.getPrototypeOf()
This new method returns the prototype of a specified object.
Using native JSON
Firefox 3.5 has native support for JSON.
New trim methods on the String object
The String object now has trim(), trimLeft(), trimRight(), and startsWith() methods.

Other improvements

  • Implicit setting of properties in object and array initializers no longer execute setters in JavaScript. This makes the behavior of setting the values of properties more predictable. See the blog post Object and array initializers should not invoke setters when evaluated for details. FIXME: Broken Link. Maybe this is copy: https://dev.mozilla.jp/localmdc/localmdc_11696.html

Document Tags and Contributors

Contributors to this page: Sheppy, Midnightaz, ethertank, Sephr, kscarfone, Nik_Martin, Potappo, user01
Last updated by: kscarfone,