Bug 23097

Summary: Why does WebKit run into JavaScript1.7 blocks without supporting any feature of JavaScript 1.7
Product: WebKit Reporter: Georg Maaß <georg>
Component: JavaScriptCoreAssignee: Nobody <webkit-unassigned>
Status: RESOLVED DUPLICATE    
Severity: Normal CC: abarth, anders.norgaard, annevk, ggaren, jchaffraix, webmaster
Priority: P3 Keywords: NeedsReduction
Version: 528+ (Nightly build)   
Hardware: Mac   
OS: OS X 10.5   
URL: https://developer.mozilla.org/en/New_in_JavaScript_1.7
See Also: https://bugs.webkit.org/show_bug.cgi?id=87527

Description Georg Maaß 2009-01-04 06:18:06 PST 
Why does WebKit run into JavaScript1.7 blocks without supporting any feature of JavaScript 1.7. From the results of my tests, I confirm Safari 3.2 supporting JavaScript 1.6, but testing those language features that make the difference between 1.6 and 1.7 WebKit 528+ fails in each test case. It neither supports block scope variables using the new keyword let nor does it support generators using the new keyword yield nor does it support de structuring assignments.

Without implementing these language features, it should not run into javascripts with language="javascript1.7" or type="application/javascript;version=1.7" because those scripts usually make use of exactly those language features not yet implemented in WebKit.
Comment 1 Julien Chaffraix 2012-05-29 11:44:20 PDT 
CC'ing some (I hope relevant) people.
Comment 2 Adam Barth 2012-05-29 16:32:06 PDT 
This area is a bit of a mess.  My understanding is that TC39 has abandoned out-of-band versioning for JavaScript.  We execute whatever types the HTML5 spec tells us to execute.
Comment 3 Alexey Proskuryakov 2012-05-30 14:51:40 PDT 
See also: bug 87527.
Comment 4 Anne van Kesteren 2023-12-02 06:47:41 PST 
We now only claim support for https://mimesniff.spec.whatwg.org/#javascript-mime-type.
Comment 5 Anne van Kesteren 2023-12-02 06:49:22 PST 
Actually, this was only very recently fixed. Let's correctly duplicate this to the bug where it was fixed.

*** This bug has been marked as a duplicate of bug 257080 ***