Section 15.2.4 of ECMA-262 specification lists toString, toLocaleString, valueOf, hasOwnProperty, isPrototypeOf and propertyIsEnumerable. WebKit currently only supports toString and valueOf. Bug #3293 covers hasOwnProperty.
Created attachment 2293 [details] Implementation of Object.prototype.toLocaleString
*** Bug 3989 has been marked as a duplicate of this bug. ***
Created attachment 2951 [details] Implementation of Object.prototype.toLocaleString Previous patch had merge conflicts.
Created attachment 2952 [details] /fast/js/object-prototype-toLocaleString.html layout test
Comment on attachment 2951 [details] Implementation of Object.prototype.toLocaleString r=me if the testing shows this matches other browsers.
Created attachment 2961 [details] /fast/js/object-prototype-toLocaleString.html better output on failure
(In reply to comment #5) Firefox and WinIE match. Mac IE doesn't, because it doesn't implement toLocaleString() at all. Upshot: I'll land the patch.
Bug #3999 tracks propertyIsEnumerable. Bug #4000 tracks isPrototypeOf. This bug is only for toLocaleString(), so I'm closing it.