Improved web apps interop promised
ECMA-262 edition 5.1 packs a number of "editorial corrections" and bug fixes that it promised will make ECMA-262 edition "easier" and allow for better interoperability among web applications. It updates edition 5, approved in December 2009 and ratified by the ISO, IEC and ECMA International.
To help further on the interoperability front, ECMA has promised it will also publish – for the first time – a standardized test suite so developers can see just how far implementations of ECMAscript adhere to the official standard.
The suite is being worked on by ECMA Technical Committee 39, whose members include Microsoft, Google, and Mozilla. The suite will be delivered in installments, with the first version planned for December and updates coming later.