12299 2011-03-14 10:26:53 +0000 The (normative and non-normative) assertion that tokenlist.item(index) / tokenlist[index] returns null for index>=length appears to be in conflict with WebIDL, at least for the index property case; afaict WebIDL requires that index property getters throw 2011-08-04 05:13:38 +0000 1 1 1 Unclassified HTML WG LC1 HTML5 spec unspecified Other other RESOLVED FIXED http://www.whatwg.org/specs/web-apps/current-work/#domtokenlist-0 P3 normal --- 1 contributor ian bzbarsky cam ian james mike Ms2ger public-html-admin public-html-wg-issue-tracking public-html-bugzilla oldest_to_newest 46668 0 contributor 2011-03-14 10:26:53 +0000 Specification: http://www.whatwg.org/specs/web-apps/current-work/multipage/urls.html Section: http://www.whatwg.org/specs/web-apps/current-work/#domtokenlist-0 Comment: The (normative and non-normative) assertion that tokenlist.item(index) / tokenlist[index] returns null for index>=length appears to be in conflict with WebIDL, at least for the index property case; afaict WebIDL requires that index property getters throw Type Error for out or range values. It may be possible per WebIDL to have .index and the index property getters do different things, but that doesn't seem like super-useful behaviour. Possibly we should throw in all cases. Posted from: 88.131.66.80 User agent: Mozilla/5.0 (X11; Linux x86_64; rv:2.0b13pre) Gecko/20110308 Firefox/4.0b13pre 46669 1 james 2011-03-14 10:32:21 +0000 Actually I think I might be wrong on what WebIDL requires; since corresponding properties for indexes outside the range are never created, trying to access such properties it will return undefined except in strict mode. Nevertheless the specs are inconsistent here. 46671 2 bzbarsky 2011-03-14 12:28:50 +0000 [index] needs to return undefined when out of range. .item(index) can do whatever it wants to. That's how nodelists already behave: .item() returns null, while [index] returns undefined. 46672 3 Ms2ger 2011-03-14 12:49:17 +0000 NodeLists can change too... 46677 4 bzbarsky 2011-03-14 13:27:29 +0000 Can they? No sites depending on the current behavior? Throwing for out-of-bounds access on nodelist, btw, is _definitely_ not web-compatible. Dunno about token list. 46679 5 james 2011-03-14 13:48:57 +0000 Right, I think the spec is *confusing* but I no longer think it is wrong except for the non-normative text which is very misleading about how out-of-bounds index access will work. I don't think it is worth trying to change the null/undefined thing; given the subtlety of their distinction, any solution will feel wrong, so we may as well just go for what is already implemented. 46686 6 Ms2ger 2011-03-14 18:49:40 +0000 Hmm, I was thinking of .item() returning undefined, but that might be hard to spec too. 46687 7 bzbarsky 2011-03-14 18:54:03 +0000 Also impossible in some language bindings, right? 46697 8 cam 2011-03-14 21:18:09 +0000 Yep. I think it is fine to leave item() return null where [n] would be undefined because the property doesn't exist. 48213 9 ian 2011-05-06 19:48:28 +0000 James, can you clarify what is confusing so that I can clear it up? I'm not 100% sure how to improve this. 48349 10 ian 2011-05-09 08:32:00 +0000 spoke to jgraham; this is about the domintro text specifically. we should make sure it doesn't imply that [index] access works like .item() access for out-of-range values. 49591 11 contributor 2011-06-14 21:56:22 +0000 Checked in as WHATWG revision r6223. Check-in comment: Simplify the non-normative descriptions of index getters to avoid confusing readers (the specifics of edge cases are rather subtle). http://html5.org/tools/web-apps-tracker?from=6222&to=6223 49592 12 ian 2011-06-14 22:03:14 +0000 EDITOR'S RESPONSE: This is an Editor's Response to your comment. If you are satisfied with this response, please change the state of this bug to CLOSED. If you have additional information and would like the editor to reconsider, please reopen this bug. If you would like to escalate the issue to the full HTML Working Group, please add the TrackerRequest keyword to this bug, and suggest title and text for the tracker issue; or you may create a tracker issue yourself, if you are able to do so. For more details, see this document: http://dev.w3.org/html5/decision-policy/decision-policy.html Status: Accepted Change Description: see diff given above Rationale: Concurred with reporter's comments on IRC. 49676 13 Ms2ger 2011-06-16 09:17:55 +0000 Updated DOM Core accordingly. http://dvcs.w3.org/hg/domcore/rev/9ef55e2543bd 53414 14 mike 2011-08-04 05:13:38 +0000 mass-move component to LC1