20105 2012-11-27 18:56:53 +0000 Nothing in the spec really defines how changes to token lists change the underlying string 2012-12-07 13:17:46 +0000 1 1 1 Unclassified WebAppsWG DOM unspecified PC Windows 3.1 RESOLVED FIXED P2 normal --- 1 bzbarsky annevk bugs erik.arvidsson mike www-dom public-webapps-bugzilla oldest_to_newest 78939 0 bzbarsky 2012-11-27 18:56:53 +0000 In particular, I see the following problems: 1) It's not clear at what point token list mutators call setAttribute in the case of .classList. If I call remove("a", "b"), should that do two setAttribute calls or just one? The difference is content-detectable using mutation records. 2) Nothing really says that the underlying attribute is modified. For example, http://dom.spec.whatwg.org/#dom-domtokenlist-remove just calls into http://dom.spec.whatwg.org/#remove-a-token-from-a-string which produces a string called "output" and never does anything with it. So per spec as currently written, "output" should just be discarded, which is bogus. 78942 1 annevk 2012-11-27 19:12:52 +0000 And here I was hoping nobody would notice. Do you support making it a single change to the attribute? 78948 2 bzbarsky 2012-11-27 19:30:49 +0000 Single change to the attribute would be fine by me, I think; it's just a bit more painful to implement. Olli? 78949 3 bugs 2012-11-27 19:43:46 +0000 Single change sounds good to me. 79409 4 annevk 2012-12-04 15:57:02 +0000 I defined this to the extent that whenever DOMTokenList is mutated the corresponding attribute is mutated. I still need to define the other way around, setting the attribute updating the DOMTokenList (the algorithm is already there, I just need to redo some of the infrastructure around attributes). 79410 5 erik.arvidsson 2012-12-04 15:58:11 +0000 WebKit implements this as a single change to the attribute. I think this is important for performance reasons too. 79644 6 annevk 2012-12-07 13:17:46 +0000 https://github.com/whatwg/dom/commit/25d3e7c0ec9cb92373e30c7bc9a3bc90840072e3 https://github.com/whatwg/dom/commit/8f66f8fe624978ecad6aa00e02db0203dbac14b2