Re: [whatwg] Please consider simplifying authoring guidance for the img alt attribute
There was some recent feedback on the img alt attribute. I have quoted some of it below. I haven't changed the spec: none of the points raised were new information. On Mon, 2 Aug 2010, Markus Ernst wrote: Am 01.08.2010 11:43 schrieb Tantek Çelik: http://wiki.whatwg.org/wiki/Img_Alt My personal opinion on the alt attribute is that: - it should only be used if the image is crucial for understanding the content, or for navigation (such as headline or link images or charts) - it's absence should default to what is alt= in HTML4 - search engines should generally ignore text in the alt attribute, but evaluate the title attribute instead Rationale: 4.8.1.1.12 says: A corollary to this is that the alt attribute's value should never contain text that could be considered the image's caption, title, or legend. It is supposed to contain replacement text that could be used by users instead of the image; it is not meant to supplement the image. The title attribute can be used for supplemental information. The most common use cases of @alt are (at least as far as I know from my authoring practise): - Insert the text contained in a headline or link image - Insert an empty string to make the page validate - Insert a short description of the image, preferably containing some keywords for search engines; sometimes the search engine aspect is weighted even higher than the contents of the image here Only the first one of these use cases matches the gideline given in 4.8.1.1.12. The second one is not harmful, exept some minimal bandwidth impact. But the third one is actually counterproductive with regard to accessibility. An image which conveys information, if it is not a text replacement (such as a headline or link image), a corporate logo, or some kind of chart, is usually almost impossible to describe in a way that can't be considered the image's caption, title, or legend. Usually, the information conveyed by the image is either duplicated in the text that the image is associated to (or in it's caption or legend), or at all useless for anybody that does not see the image. Either way, the presence of an alt text does not provide useful information, but possibly confuses - specially if it is written with regard to search engines. I am confident that declaring the alt attribute as optional would not only simplify the spec and validation, but also have no significant effect regarding accessibility, as poor authoring cannot really be prevented by structural means. And I am also confident that if search engines ignored the alt attribute, and authors were encouraged to only insert alt text if helps to understand the content, this would have a positive effect on accessibility, as authors would be discouraged to put unnecessary information in the alt attribute for seo purposes, or duplicate the legend or caption (what I used to do before I read 4.8.1.1.12, because HTML4 seemed to require exactly this). On Mon, 2 Aug 2010, Ashley Sheridan wrote: What you said doesn't make sense. The alt text is to be used instead of the image, and the title is for supplemental content. Therefore, search engines should use alt text, as that is what they are attempting to convey in the lost (in the sense that search engines don't process images like they do text) image. If they used the title, one can only imagine the trouble. On Tue, 3 Aug 2010, Markus Ernst wrote: Ok, maybe the search engine aspect obfuscates the main statement I wanted to make; let's just drop it and try to be some more specific. 4.8.1.1 says: Except where otherwise specified, the alt attribute must be specified and its value must not be empty; the value must be an appropriate replacement for the image. The specific requirements for the alt attribute depend on what the image is intended to represent, as described in the following sections. In the sub sections, many cases are stated where the alt attribute must be set to the empty string, and some cases where the alt attribute can even be omitted. These seem to be the ones that are considered to be too complicated. My point is, that it would simplify things (e.g. the cases treated in the links Tantek provided) a lot to do it the other way around: - Declare the alt attribute as optional, and default a missing alt attribute to alt= - Explicitly specify the cases where the alt attribute must be set (e.g.: if the image is the only child of an a or h1-6 element) - Update some of the authoring guidance in the sense of encouraging authors to apply alt text where appropriate, and omit it where not (I specially think of 4.8.1.1.9 here; I will post a separate proposal about this section) I doubt that there is much benefit in the requirement for the alt attribute, for the following reasons: - The paedagogig aspect of making a document invalid if an alt attribute is omitted is obsolete, as authors have got used to just insert
Re: [whatwg] Please consider simplifying authoring guidance for the img alt attribute
On Tue, 2010-08-03 at 11:58 +0200, Markus Ernst wrote: Am 02.08.2010 20:54 schrieb Ashley Sheridan: On Mon, 2010-08-02 at 17:19 +0200, Markus Ernst wrote: - search engines should generally ignore text in the alt attribute, but evaluate the title attribute instead Rationale: 4.8.1.1.12 says: A corollary to this is that the alt attribute's value should never contain text that could be considered the image's caption, title, or legend. It is supposed to contain replacement text that could be used by users instead of the image; it is not meant to supplement the image. The title attribute can be used for supplemental information. What you said doesn't make sense. The alt text is to be used instead of the image, and the title is for supplemental content. Therefore, search engines should use alt text, as that is what they are attempting to convey in the lost (in the sense that search engines don't process images like they do text) image. If they used the title, one can only imagine the trouble. Ok, maybe the search engine aspect obfuscates the main statement I wanted to make; let's just drop it and try to be some more specific. 4.8.1.1 says: Except where otherwise specified, the alt attribute must be specified and its value must not be empty; the value must be an appropriate replacement for the image. The specific requirements for the alt attribute depend on what the image is intended to represent, as described in the following sections. In the sub sections, many cases are stated where the alt attribute must be set to the empty string, and some cases where the alt attribute can even be omitted. These seem to be the ones that are considered to be too complicated. My point is, that it would simplify things (e.g. the cases treated in the links Tantek provided) a lot to do it the other way around: - Declare the alt attribute as optional, and default a missing alt attribute to alt= - Explicitly specify the cases where the alt attribute must be set (e.g.: if the image is the only child of an a or h1-6 element) - Update some of the authoring guidance in the sense of encouraging authors to apply alt text where appropriate, and omit it where not (I specially think of 4.8.1.1.9 here; I will post a separate proposal about this section) I doubt that there is much benefit in the requirement for the alt attribute, for the following reasons: - The paedagogig aspect of making a document invalid if an alt attribute is omitted is obsolete, as authors have got used to just insert alt= if they are too lazy to write an alternative text, and many authoring tools even insert the empty string by default if the author does not specify an alt text. Bad authoring cannot be prevented by structural specification. - I have no personal experience using screen readers or text-only browsers, but I am quite sure that unnecessary (not speaking of inadequate) alt text is not helpful, but even harmful as it interrupts the reading or listening flow. (If screen reader or braille browser users contradict me here, I am happy to learn, of course.) If the content of the alt attribute is interrupting the flow of the text, then it is either not describing the image it represents well, or the image is not something which should appear in the flow of text at that position. HTML5 brings many new layout devices which can help lay out the code in a logical and coherent manner, while still rendering on screen in the traditional manner. I do test thing in text browsers, and frequently see bad alt text markup on sites along the lines of alt=Company Logo or somesuch, where in-fact it should have read alt=ACME Trading Co. because that is the text that was on the image anyway. I agree that there is a lot of bad markup out there with lots of empty alt attributes, inserted only to pass the validators, but I think making the attribute optional would just cause further accessibility issues. Better to improve the validators to give warnings about empty alt attributes (only warnings rather than outright errors) to notify the developer that there could be a potential issue with the markup. Thanks, Ash http://www.ashleysheridan.co.uk
Re: [whatwg] Please consider simplifying authoring guidance for the img alt attribute
Am 01.08.2010 11:43 schrieb Tantek Çelik: http://wiki.whatwg.org/wiki/Img_Alt I encourage fellow web authors to add opinions/comments. My personal opinion on the alt attribute is that: - it should only be used if the image is crucial for understanding the content, or for navigation (such as headline or link images or charts) - it's absence should default to what is alt= in HTML4 - search engines should generally ignore text in the alt attribute, but evaluate the title attribute instead Rationale: 4.8.1.1.12 says: A corollary to this is that the alt attribute's value should never contain text that could be considered the image's caption, title, or legend. It is supposed to contain replacement text that could be used by users instead of the image; it is not meant to supplement the image. The title attribute can be used for supplemental information. The most common use cases of @alt are (at least as far as I know from my authoring practise): - Insert the text contained in a headline or link image - Insert an empty string to make the page validate - Insert a short description of the image, preferably containing some keywords for search engines; sometimes the search engine aspect is weighted even higher than the contents of the image here Only the first one of these use cases matches the gideline given in 4.8.1.1.12. The second one is not harmful, exept some minimal bandwidth impact. But the third one is actually counterproductive with regard to accessibility. An image which conveys information, if it is not a text replacement (such as a headline or link image), a corporate logo, or some kind of chart, is usually almost impossible to describe in a way that can't be considered the image's caption, title, or legend. Usually, the information conveyed by the image is either duplicated in the text that the image is associated to (or in it's caption or legend), or at all useless for anybody that does not see the image. Either way, the presence of an alt text does not provide useful information, but possibly confuses - specially if it is written with regard to search engines. I am confident that declaring the alt attribute as optional would not only simplify the spec and validation, but also have no significant effect regarding accessibility, as poor authoring cannot really be prevented by structural means. And I am also confident that if search engines ignored the alt attribute, and authors were encouraged to only insert alt text if helps to understand the content, this would have a positive effect on accessibility, as authors would be discouraged to put unnecessary information in the alt attribute for seo purposes, or duplicate the legend or caption (what I used to do before I read 4.8.1.1.12, because HTML4 seemed to require exactly this).
Re: [whatwg] Please consider simplifying authoring guidance for the img alt attribute
On Mon, 2010-08-02 at 17:19 +0200, Markus Ernst wrote: - search engines should generally ignore text in the alt attribute, but evaluate the title attribute instead Rationale: 4.8.1.1.12 says: A corollary to this is that the alt attribute's value should never contain text that could be considered the image's caption, title, or legend. It is supposed to contain replacement text that could be used by users instead of the image; it is not meant to supplement the image. The title attribute can be used for supplemental information. What you said doesn't make sense. The alt text is to be used instead of the image, and the title is for supplemental content. Therefore, search engines should use alt text, as that is what they are attempting to convey in the lost (in the sense that search engines don't process images like they do text) image. If they used the title, one can only imagine the trouble. Thanks, Ash http://www.ashleysheridan.co.uk
[whatwg] Please consider simplifying authoring guidance for the img alt attribute
With acknowledgement of existing issues (e.g. http://www.w3.org/html/wg/tracker/issues/80 ) on the topic: Summary: Please consider simplifying authoring guidance for the img alt attribute, such as dropping the document is an e-mail and meta generator cases. More details provided on the wiki: http://wiki.whatwg.org/wiki/Img_Alt I encourage fellow web authors to add opinions/comments. Thanks! Tantek -- http://tantek.com/ - I made an HTML5 tutorial! http://tantek.com/html5
