- From: Ian Hickson <ian@hixie.ch>
- Date: Tue, 6 May 2008 06:08:15 +0000 (UTC)
On Sat, 7 May 2005, Christian Biesinger wrote: > > OK, another <object> fallback question: Consider an object that has no > attributes that would allow selecting a plugin/content handler. For > simplicity, consider an object without any attributes, say: > > <object>Foo</object> > > What should be displayed? Should the user agent just fall back to the > contents of the object? (Presumably "empty string" as fallback content > does not affect the answer to this question either :-) ) The spec now defines this. On Wed, 25 Jan 2006, Hallvord Reiar Michaelsen Steen wrote: > > On encountering an OBJECT, the UA must check type and/or classid. > > If the type attribute identifies a file type the UA handles > internally, check if the OBJECT has a data attribute. Render contents > of this attribute if found, proceed to fallback contents if not. > > If type/classid identifies a known plugin, the UA must initialise the > plugin passing on information about the attributes and the name/value > pairs of any PARAM descendants that are not children of nested OBJECT > tags. > > If type/classid does not identify a known plugin, and there is a data > attribute, do a HEAD request on the resource identified by the data > attribute. If the server sends a content-type that identifies a known > plugin, initialise plugin. > > If there is no data attribute, the resource can not load or the > content-type of the resource is unknown, proceed to render fallback > contents. The above is somewhat what the spec says, though it is more closely aligned with what browsers (Mozilla in particular in this case) seem to do. > Issues: if there is a known content-type and a data: attribute, > should the UA check if the content-type sent from server also > identifies the plugin? In other words, do we want to say that the > type attribute on the OBJECT tag is only a hint and that the actual > HTTP content-type header is the one that counts? Right now the spec uses the Content-Type header if it is present. > I'm not sure if "only a hint" should be speced. It sounds quite risky to > meddle with the logic for embedding contents - could break many sites, > particularly if we are supposed to start relying on the famously > malconfigured HTTP content-type responses. What should it be instead? > Since there are use cases for plugins that do not load data at all, the > UA should initialise the plugin even without data attribute if the type > is known. That sort of negates the point about type being a hint because > we can't initialise one plugin, look at the content-type of files that > plugin decides to request and say "whops, we started the wrong plugin, > let's do this again". If the spec goes the "hint" route, it really needs > to make that apply only to OBJECTs with a data attribute, and to > minimise problems with malconfigured servers it should only take place > if the UA doesn't know the specified type attribute IMO. Right now if type="" is present but data="" isn't then the respective plugin is fired, otherwise the plugin to fire is taken from the Content-Type header. > Another issue is of course if and how one should map classid to plugins. Indeed. I don't know how to do that. I suppose it is UA-specific. On Tue, 31 Jan 2006, Shadow2531 wrote: > > The current methods of "The server Content-Type rules all" and "If > there's no data attribute, then fail" are not working out. There are > cases where a data attribute is not needed and there are cases where a > type attribute should be the priority. The type attribute is really used > as "Here's what plug-in/handler I want to use". For the no-data="" case, the spec now handles it. > There also needs to be some specifics for the classid attribute. If the > classid contains an unsupported naming scheme, should the UA really have > to just fail or should it go on and try to use the type and data > attributes? It appears it should fail. Do browsers do otherwise? > How should data uris be handled? Is it just up to the plug-in to handle > the passed data uri or is the UA allowed to create a file from the data > URI and pass the file path to the plug-in/hander (if it can do it > safely)? Isn't this up to the plugin API? > What should happen when a UA encounters a codebase attribute that has a > path to a cab file instead of a base URI? Should the UA always use the > codebase to resolve URIs even if it has junk in it? Right now codebase="" is just ignored by the spec. What should it do? > First, the UA should check for a classid attribute. > > If present and the the UA has a handler associated with the specified > naming scheme, then the UA should pass all arguments to the handler in a > manner that is specific to the handler. That's what the spec says, indeed. > If the classid attribute is not present or the naming scheme is not > supported or the handler returns an error code, then the UA must check > for the presence of a type attribute. If classid="" isn't supported, it just shows fallback. > If it exists, the UA must check to see if it has a handler associated > with the Content-Type specified in the type attribute. > > If the Content-Type is associated with a handler, the UA must pass all > arguments to the handler. The resource is actually downloaded by the UA in this case, as far as I can tell. Is that wrong? > If that fails and there is a data attribute, check the Content-Type > sent by the server for the file and determine if there's a handler > associated with the type. The spec honours the Content-Type header over all else if it is present and classid="" isn't. > If there is a handler associated with the type, pass all arguments to > the handler. > > If there is not, the UA *should* compare the file extension to a list > of known Content-Types associated with that extension. > > If a handler is found, pass all arguments to the handler. I do not want to add any extension-sniffing to the spec, it is too dangerous, highly unreliable, and as far as I can tell isn't necessary. > ( URIs to files should be passed to the handler and the handler should > download the files as necessary. The Ua should not download the file on > its own. Only the handler should make that request to the UA.) Really? > Once the handler gets the arguments, it *must* detmermine whether it has > the necessary and valid arguments to initialize. If it does not, it > should return a failure code. If it does, it should try to initialize > and if successful, return a success code; otherwise, return a failure > code. The handler should return a failure code in every situation where > there's no need to initialize in the first place. This is out of our scope. > The UA must check for this return code to determine whether to display > fallback content. It's not clear to me how to tell if a plugin failed. On Wed, 1 Nov 2006, Christoph P?per wrote: > > I think it would be helpful to /explicitly/ allow content types (alias > media types) in |type| of |object| to omit the subtype, e.g.: > > <object type="video" data="foo.mpv"/> > <object type="audio" data="foo.mpa"/> > <object type="image" data="foo.png"/> ~= <img src="foo.png"> > <object type="application" data="foo.swf"/> ~= <embed src="foo.swf"/> > <object type="text" data="foo.txt"/> ~= <iframe src="foo.txt"/> > > Maybe this is all the support for this element type that should be > required from conforming implementations. Furthermore |width| and > |height| should be required for freely scalable formats, but OTOH not > apply to 'audio' types (i.e. always equal zero), and exclude the space > required for an optional inline GUI. > > I never understood, by the way, why videos and Flash-like content > shouldn't work within |img|. (Parameters can be specified in URIs.) > > I could also envision an HTML5 where |alt| was optional for (or even > removed from) |img|, which in return was only allowed to be used for > optional, decorative images (and perhaps likewise |embed|). Every > illustration conveying meaning was then to be embedded using |object| > (including descriptive content, but nesting |object|s would be > discouraged, although allowed) or more sophisticated methods. This > wouldn't keep many correctly authored existing pages conformant, though. I don't really see how to handle this feedback. We can't really make the changes that would change how <object> works today. On Tue, 7 Nov 2006, Lachlan Hunt wrote: > > Should the data attribute be required for <object>? There is at least > one plugin that doesn't need it. XStandard embeds itself without using > it, like this: > > <object type="application/x-xstandard" id="editor1" width="100%" height="400"> > <param name="Value" value="Hello World!" /> > </object> > > I'm not sure whether that's a correct use of the object element or not, > and I do think it would make more sense for XStandard to replace a > textarea, but there must be implementation issues with that or > something. > > http://xstandard.com/page.asp?p=A4372B00-8D7F-4166-977C-64E5C4E3708E&ss=C2B75B64-1544-429D-ACDA-07D17E35FB56 It's allowed. On Tue, 7 Nov 2006, Shadow2531 wrote: > > Reason 1: > <object classid="java:MyJavaClass"></object> is used for Java. ( > Although I'd love to have <object type="application/java" > data="file.class"></object> work, but ...) This is not allowed. Java should use the standard mechanism, as you point out. > Reason 2: > You might want to load a plugin like this: <object > type="application/x-mplayer2"></object> and later use scripting to > tell the plugin to get the resource. If the data attribute is > required, you'd be forced to load a resource that you didn't want to. Indeed. > Reason 3: > The tcl plugin <http://www.tcl.tk/software/plugin/> suports inline > scripts via a script param and things like the following need to work > without the data attribute. > > <object type="application/x-tcl"> > <param name="script" value="script content"> > </object> Indeed. On Sat, 23 Dec 2006, Rohan Prabhu wrote: > > I've been writing a spec called 'XObject' for the past week.. and i'm > going on a 2-day vacation from tomorrow.. just got the idea of sharing > this with you. I wrapped it up in a small site-like thingy in the short > time i had.. so the site is not really good... but the content is there > as much as i have worked on. It is still a work in progress. Do read the > foreword there, I've already warned about some factual inaccuracies... > :) > > Here is the link to it: http://xobject.tritiumx.com It's not clear to me what this spec (which btw is now no longer available) was supposed to address. On Sat, 7 Apr 2007, Henri Sivonen wrote: > > HTML5 should probably make the Java applet embedding patterns documented by > Sun conforming or at least make the <applet> case conforming as it is the > cross-browser syntax: > http://java.sun.com/j2se/1.5.0/docs/guide/plugin/developer_guide/using_tags.html Java needs to get over itself and stop being such a drama queen and just use the standard embedding methods that everyone else uses. On Sat, 7 Apr 2007, Michael A. Puls II wrote: > > Currently, the only way to embed an applet that's allowed by the spec > is: > > <object type="application/x-java-applet"> > <param name="code" value="MyJavaClass"> > <object> > > (That works fine for Opera and FF at least.) Indeed. > There's also <embed type="application/x-java-applet" > code="MyJavaClass">, which is currently not allowed because src is > required. Indeed. > There's also <object classid="java:MyJavaClass> (which is used as a > non-deprecated example at > <http://www.w3.org/TR/html4/struct/objects.html#h-13.4>). This is > currently not allowed because there's no classid allowed, which has to > be present to be compatible with IE. Right. > And, then, there's of course APPLET, which needs to be defined (no > rush), including how fallback content works when java support isn't > present and the alt attribute is present. (As in, does alt get used over > fallback content or the other way around or somewhere in between.) There's a note in the spec about this. > I also think it might be necessary to clarify (or at least hint to) > what mime type should trigger java. application/x-java-vm and > application/x-java-applet etc. are provided by the Sun Java plug-ins, > but not all browsers use those plug-ins. (application/java is used in > W3C examples.) The spec has an example with x-java-applet now. > On a side, if codebase is allowed on the object element, it will have 3 > different uses. > > 1. base URI for resolving (kind of like <base href="">) > 2. URI to a .cab file (for activeX stuff) > 3. For java, it's specifically a URI to the directory the .class file > is in unless you're using current IE in which case, it's #2 and a > codebase param is used instead. o_O I'd rather just not support it and make it non-conforming... Do any browsers actually support case 1? Case 2 seems incompatible with case 1. > In the case of #3 (for browsers besides current IE), where both a > codebase attribute and a codebase param are present, one of them would > have to override the other. It might be necessary to define which one > and how etc. (Going to something specific like this might be out of > scope for plug-ins etc. in general, but Java handling might be an > exception.) > > With all the different OBJECT situations for Java, APPLET will be a huge > relief. How about just not supporting Java? On Mon, 22 Oct 2007, Vlad Alexander (xhtml.com) wrote: > > I noticed that the latest HTML 5 draft states that the "name" and > "codebase" attributes are not allowed on the "object" element. > > 1. Plug-ins, such as XStandard, use the "name" attribute for submitting > content to the server without the need for JavaScript. This makes for an > accessible solution. XStandard has been doing this for 4 years in some > browsers. IE, Firefox and Opera support this feature. This attribute > serves a vital role for plug-ins. name="" is now supported, though not for this purpose. > 2. The "codebase" attribute is the only way to auto-install or update > plug-ins in IE. This is an important feature that should not be removed > without providing an alternative solution. I take it you don't like the idea of HTML+JS being the alternative solution? Auto-installing unprotected binary code on an enduser machine seems unbelievably unwise. > 3. The HTML 5 draft states that the "embed" element is used for plug-in > content. The "object" element is a better mechanism for loading plug-ins > and is supported by all browsers. The HTML 5 spec should state the > "embed" or "object" elements can be used for loading plug-ins. I'm not sure which bit you're referring to here. On Thu, 25 Oct 2007, Michael A. Puls II wrote: > > Yes, I agree. The name attribute has to be supported (at least when the > object is inside <form>. (All the form stuff hasn't been dealt with yet > though.) It's not clear to me how this is supposed to work. Does the NPAPI define a way to submit form data? > > 2. The "codebase" attribute is the only way to auto-install or update > > plug-ins in IE. This is an important feature that should not be > > removed without providing an alternative solution. > > If we do define it, it's going to be fun because what it's for depends > on how it's used. > > It can be a URI to fetch a new version (for IE). > It could be the directory that java class files are in (in browsers > besides IE when using the Sun java plugin). > It could be a base URI used for resolving relative URIs (in browsers > besides IE for possibly native stuff and some plugins). > > For the last 2, there would need to be rules to follow to determine > whether it's an IE upgrade URI or a base URI so browsers besides IE > don't use it as a base path if it's not really a base path. But, > there's not much need to use a codebase attribute in FF, Opera and > Safari (not even for java). I have no idea what to do here. On Tue, 1 Jan 2008, Jeff Walden wrote: > > http://biesi.damowmow.com/object/011.html > > Firefox 2 shows FAIL. > Firefox 3 currently shows PASS. > WebKit nightly shows a broken image icon. > Opera 9.25 shows PASS. WebKit now shows PASS, so this seems like a non-issue. (Spec agrees.) > http://www.whatwg.org/specs/web-apps/current-work/multipage/section-embedded0.html#the-object > > For the moment ignoring that WebKit's using @type instead of the > server-sent type of the <object> producing the PASS/FAIL/icon (contrary > to current HTML5 and HTTP RFC 2616), it seems that WebKit isn't > displaying fallback content when the primary content contains "errors" > -- malformed images, in this case -- where recent Firefox and Opera are. > > The spec doesn't currently address falling back for malformed content, > i.e. malformed images, invalid XML (maybe?), content a plugin handler > declines to handle (?, dunno whether this is expressible in NPAPI or > ActiveX or whether that question's too implementation-dependent), etc. > I tend to think it should since a broken-image icon's not particularly > useful, but I don't care strongly one way or the other. Fixed for everything but XML. -- Ian Hickson U+1047E )\._.,--....,'``. fL http://ln.hixie.ch/ U+263A /, _.. \ _\ ;`._ ,. Things that are impossible just take longer. `._.-(,_..'--(,_..'`-.;.'
Received on Monday, 5 May 2008 23:08:15 UTC