7104 2009-07-14 19:41:46 +0000 Disagreement on handling of null value for localStorage.setItem() 2009-08-09 23:12:35 +0000 1 1 1 Unclassified WebAppsWG Web Storage (editor: Ian Hickson) unspecified Macintosh MacOS X RESOLVED WONTFIX P2 normal --- 1 brett ian ian jorlow mike public-webapps public-webapps-bugzilla oldest_to_newest 25963 0 718 brett 2009-07-14 19:41:46 +0000 Created attachment 718 test page that shows what localStorage.getItem() thinks null should be In Safari 4, if you use null as a value when setting a new key it will end up returning the string "null". But in Firefox 3.5, you get back null itself. I have attached a dead-simple HTML file that shows the differences when run in the two browsers. Not sure who is right since the spec says a DOMString is expected and I am not sure if null is considered a valid DOMString. And in both browsers you end up with a key being set. While in Safari that makes sense since you are getting back a string, but in Firefox that's confusing as the value for the key is the same as the value used to signify that no value exists for the key. That means in Firefox the only way to know that the key is actually set explicitly to null is to iterate through all the keys using localStorage.key() to try to see if the key has actually been given a value. 25967 1 jorlow 2009-07-15 02:03:13 +0000 I brought this up on WhatWG a while ago. I believe it was agreed that Firefox's implementation goes against the spec. 25968 2 brett 2009-07-15 04:36:07 +0000 (In reply to comment #1) > I brought this up on WhatWG a while ago. I believe it was agreed that > Firefox's implementation goes against the spec. > Best I could find was http://lists.whatwg.org/pipermail/whatwg-whatwg.org/2008-April/014383.html which ended with someone believing that Firefox is wrong and Safari is right, but no definitive answer. 25970 3 jorlow 2009-07-15 07:21:19 +0000 I apologize...I must have been remembering incorrectly. I couldn't even find any mentions of any such message in my email archive, which further confounds me. So yes, I suppose it is good to double check and perhaps have specific language in the spec to settle the issue once and for all. :-) From my reading, the Safari way of doing things is definitely the correct one. The rational is essentially what you already mentioned, Brett. If not, a .contains method should be added...but writing code for such an interface seems cumbersome. 25981 4 brett 2009-07-15 18:34:26 +0000 Although my opinion counts for squat, I do agree with Safari's behavior as well. Coercion of an object to a string is common enough in JS that it is reasonable to have null coerced. It did catch me by surprise that it did that, but I chalk that up to lack of JS experience on my part. And once an official decision is made on this I will report the proper behavior to the right browser folks. 26332 5 ian 2009-08-09 22:04:35 +0000 I propose to make the spec just use the default behaviour specified by Web IDL. 26336 6 brett 2009-08-09 22:57:55 +0000 Could you tell me what that means, Ian? I am writing a localStorage wrapper to deal with browser incompatibilities and add some helper functions and I would like to keep the wrapper agreeing with the spec. 26337 7 ian 2009-08-09 23:05:30 +0000 I'm not 100% sure, as this has changed a few times, but it appears: http://dev.w3.org/2006/webapi/WebIDL/#TreatNullAs ...that it means that null and undefined, when passed to methods accepting DOMStrings, treat them as the strings "null" and "undefined" respectively. 26341 8 brett 2009-08-09 23:12:35 +0000 Thanks for the clarification, Ian! That's what I figured; just pass all key/value arguments through String. That leaves Firefox 3.5 incompatible in this instance and (I believe) a bug report has been sent in. And as an aside for anyone curious how FF 3.5 and Safari 4 are incompatible with the spec so far, both do not implement ``localStorage.key(localStorage.length)`` properly as they both throw an exception instead of returning null. I reported the appropriate bugs. Otherwise they seem to be following the spec. 718 2009-07-14 19:41:46 +0000 2009-07-14 19:41:46 +0000 test page that shows what localStorage.getItem() thinks null should be web_storage.html text/html 701 brett PGh0bWw+Cjxib2R5PgogICAgPHA+c2V0SXRlbSB3aXRoIG51bGw6ICI8c3BhbiBpZD0idXNlLW51 bGwiPlhYWDwvc3Bhbj4iICh0eXBlb2YgPHNwYW4KICAgICAgICBpZD0idmFsdWUtdHlwZSI+WFhY PC9zcGFuPik8L3A+CiAgICA8cD5OdWxsIGNyZWF0ZXMgYSBrZXkgZW50cnk/IDxzcGFuIGlkPSJu ZXcta2V5Ij5YWFg8c3Bhbj48L3A+CjxzY3JpcHQgdHlwZT0idGV4dC9qYXZhc2NyaXB0Ij4KICAg IGxvY2FsU3RvcmFnZS5jbGVhcigpOwogICAgdmFyIGtleSA9ICJ0ZXN0IGtleSI7CiAgICBsb2Nh bFN0b3JhZ2Uuc2V0SXRlbShrZXksIG51bGwpOwogICAgdmFyIG51bGxfcmVwb3J0ID0gZG9jdW1l bnQuZ2V0RWxlbWVudEJ5SWQoInVzZS1udWxsIik7CiAgICB2YXIgdmFsdWUgPSBsb2NhbFN0b3Jh Z2UuZ2V0SXRlbShrZXkpOwogICAgbnVsbF9yZXBvcnQuaW5uZXJIVE1MID0gdmFsdWU7CiAgICB2 YXIgdHlwZW9mX3JlcG9ydCA9IGRvY3VtZW50LmdldEVsZW1lbnRCeUlkKCJ2YWx1ZS10eXBlIik7 CiAgICB0eXBlb2ZfcmVwb3J0LmlubmVySFRNTCA9IHR5cGVvZiB2YWx1ZTsKICAgIHZhciBrZXlf Y291bnRfcmVwb3J0ID0gZG9jdW1lbnQuZ2V0RWxlbWVudEJ5SWQoIm5ldy1rZXkiKTsKICAgIGtl eV9jb3VudF9yZXBvcnQuaW5uZXJIVE1MID0gbG9jYWxTdG9yYWdlLmtleSgwKTsKPC9zY3JpcHQ+ CjwvYm9keT4KPC9odG1sPgo=