There is also a new for each loop:

for each (var item in [1,2,3])

However, I'm not sure whether this is an official feature of JavaScript 1.6. This construction is required by E4X but it was made available to usual scripts as well - I don't know whether this was intentional. --Wladimir Palant 16:41, 12 September 2005 (PDT)

Fx 1.5b2 now has E4X syntax extensions enabled by default in HTML with the exception of XML comments: bug 309242. I'm not familiar with E4X, so someone else please update the article. --Maian 00:15, 7 October 2005 (PDT)