Monthly Archives: October 2006

Fixing HTML

Earlier today, Joe Clark responded to Tim Berners-Lee’s announcement of the W3C’s new plan for HTML. Joe has argued that fixing HTML is not as important as accessibility, and that the WCAG working group is in much more serious trouble than the HTML working group. For this, he seems to be criticizing the W3C’s decision.

He has also criticised the WHATWG and their work on HTML 5, claiming that they’re making the same mistakes as the W3C, and raised several issues and suggestions for improving HTML.

Working Groups

I’m not disputing his claims about the problems with the WCAG working group or the WCAG 2.0 guidelines. In fact, I agree with him in that regard. But to imply that that the W3C doesn’t need to do anything about (X)HTML or the HTML working group is misguided. Something desperately needs to be done with each of the HTML, XForms and WCAG working groups; they’re all in serious trouble and their problems need to be fixed.

The W3C’s decision to deal with the HTML working group is at least a step in the right direction. Whether the chosen path is right or wrong is yet to be seen and I’m trying to reserve judgment until more information is available. But I promise, as soon as the information I’ve asked for becomes available, I’ll review it thoroughly.

The Problems with HTML

HTML is a topic of interest. But it isn’t an outright fiasco. HTML, in large part, works fine right now.

It is true that HTML 4.01 itself isn’t a total fiasco. In many ways, it works. We’ve been using it for years without too many problems and will continue to do so for many years to come. However, there are many problems and limitations with it that need to be addressed.

There are also many problems with the W3C’s HTML working group, who have been ignoring the needs of real world developers and pushing ahead with a language that is doomed to failure. They’ve not only completely ignored backwards compatibility issues, but have failed to adequately address many other issues that have been raised.

For instance, they don’t consider error handling to be important for interoperability. They’ve made vague statements about how they don’t need to define error handling, how browsers should just refuse to handle erroneous content, and they don’t care if different browsers handle it differently.

The Process

…which means that, with the W3C’s glacial processes, we’ll have a spec document to look at in 2010 and actual browser support in 2012.

Yes, it is true that specs do take a long time to write and a long time to implement, but there are reasons for that. The process involves many steps, designed to help ensure the quality of the final specification. But, due to the process, actual browser implementation must occur before the spec can be finished, not years afterwards.

Criticisms of the WHATWG and HTML 5

My concern is that WHAT WG is doing exactly what the W3C did. Due in no small part to WHAT WG’s leadership by a strict standardista with an interest in video games, “HTML5” replicates HTML’s obsession with computer-science and math elements.

  • HTML has samp, var, and kbd. I use all of them and I am pretty much the only one who does.

How is HTML 5 repeating the same mistakes? HTML 5 did not introduce code, kbd, samp and var, they have been retained from HTML 4 and there is no reason to remove them. HTML 5 has not yet introduced any more elements specifically for computer science and mathematics. In fact, so far, proposals specifically for mathematics have, at this stage, been rejected mostly due to backwards compatibility and complexity issues.

The following is a list of all of the elements introduced in the current drafts of HTML 5 (I hope I didn’t miss any).

Of all of those new additions, which ones specifically fall into the category of computer science and/or mathematics?

  • But, true to member biases, “HTML5” bans the use of dldt/dd for dialogue, a usage permitted by the HTML spec and in wide use by intelligent developers like me who have to mark up documents unrelated to computer science. (They’d prefer you use a thicket of blockquotes and cites. And, presumably, nullify all the indention and italicization that browsers will do by default.)

This is a complex issue. Many people have argued in the past that definition lists are strictly for marking up definitions, and that the description about using it to markup dialogue given in the HTML 4.01 spec is a mistake. But, in my view, such arguments are based mostly on the name of element, rather than its actual definition. The definition list, which I think should be called a description list (or association list), has proven much more useful in the real world as a generic structure for many kinds of name/value, term/description, or key/value pairs, and reserving it strictly for definitions is not very practical.

The current HTML 5 draft recognises this, but still notes that that it is inappropriate for dialogue. This issue was raised on the list recently and, at this stage, should be considered an open issue.

This is a classic problem in HTML development: The people doing the work are geeks with computer-science interests who do not understand, for example, newspapers, or screenplays, or, really, print publishing in general. In some obscure way, they disdain print publishing, as the Web is not print. Indeed it isn’t, but print has structures the Web doesn’t, and it doesn’t have them because people like these refuse to acknowledge they exist or simply refuse to consider them.

I am not going to disagree with that but, Joe, as you clearly do know about such things, why don’t you get involved? If you, or anyone else presents use cases and other real world evidence that supports the need for something to be added, and it can be shown that existing markup is inadequate, we can develop something to solve the problem together.

This attitude – still present in WHAT WG, though it is separate and was formed later – can be summed up as “Until we decide you are using our computer-science tags adequately, we won’t even consider the semantic needs of your documents.”

The WHATWG is not just trying to solve problems for marking up computer-science documents. What we need is to document use cases and other evidence to show that something will be useful. We don’t need to see people using non-existent markup before we’ll consider it. We need to look at what people are using and the kind of content they are publishing to see where the limitations lie with existing markup. There is no point introducing new markup if existing markup is already suitable or if people aren’t going to use it anyway, so we need evidence that they will.

Markup Suggestions

For “HTML5” and the new HTML variants, why can’t we just adopt what’s already been done in other namespaces, like the Text Encoding Initiative and tagged PDF? Yes, I really mean the latter.

We can. We just need to document things like use cases to show how such markup would be used, real world example content (from any media) for which it would be suitable, how authors are already marking up such content, the limitations of existing markup and an explanation of why new markup would be useful to authors and what benefits it provides to users.

We assuredly could use elements from tagged PDF like:

  • annotation

That’s a reasonable suggestion. Why is existing markup inadequate for this? What benefit would it provide to authors and users?

  • note and reference for footnotes, endnotes, and sidenotes (not aside in “HTML5”)

There are many examples of footnotes used on the web, such as Wikipedia for instance, and I do believe it would be a valuable addition. The difficulty is in working out the best way to mark it up.

As for notes, the XHTML Role Attribute module already has a note value for such things. Whether or not the role attribute will be included in HTML 5 is not yet clear. It’s been discussed before, but I can’t recall if the issue has been resolved or not.

  • part, section and article (some in “HTML5”)

Both section and article are already present, what benefit would the part element provide? How is it different from section? Its definition in the PDF Reference, Fifth Edition, Version 1.6 (PDF) seems rather vague:

A large-scale division of a document. This type of element is appropriate for grouping articles or sections.

It’s not clear to me when I would use it or why it would be useful to do so. Could you provide a use case?

  • caption generically applicable to tables and figures

This has been discussed before and the issue is still open. The major problem is related to backwards compatibility. Unfortunately, it’s not as simple as just using the caption element because when a caption element occurs outside of table markup, current browsers do not include the element itself within the DOM.

There is also the issue of how to associate the caption with the figure. Since, unlike table, img is an empty element, so the caption can’t be included within it. It also can’t be included inside the object element, because it would be considered fallback content and not visible in current browsers.

  • bibliographies, tables of contents, and indices (some in “HTML5”)

For tables of contents, isn’t existing list markup good enough? Would it be beneficial to explicitly mark the content as the TOC? Could the role attribute address this problem?

I don’t know much about bibliographies and indices, so no comment

  • nonstruct for generic groupings

Why is this useful? I don’t understand how it is different from div, the definition given in the PDF reference was not clear to me.

A grouping element having no inherent structural significance; it serves solely for grouping purposes. This type of element differs from a division (structure type Div; see above) in that it is not interpreted or exported to other document formats; however, its descendants are to be processed normally.

Could you provide a use case?

  • formula

Similar concepts have been discussed before. As far as I know, the issue is still open. But doesn’t that fit into the category of science and mathematics that you had issues with earlier?

Proposed Fixes

Nonetheless, aren’t the easiest fixes those that would make many nominally invalid documents valid and help accessibility?

  • Ban tables for layout.

This will no doubt be done when the table section is written. The last I heard about this was that it’s scheduled for later this year or early next year.

  • Allow fragment identifiers to start with any ASCII character, not just a letter. Suddenly hundreds of millions of Blogger comment URLs become valid.

That was a limitation of the SGML heritage of HTML, which has unfortunately been carried over into XML as a validity constraint for attributes of type ID. Note that HTML 5 is no longer considered an application of SGML, it has its own syntax requirements, but XHTML 5 is based on XML.

However, regardless of the validity constraint (as I understand it), (X)HTML 5 effectively dispenses with DTD based validity, in favour of much more rigorous conformance requirements and there is no mention of what constitutes a valid ID attribute. I believe, as long as it’s well-formed and doesn’t contain whitespace, it will be considered conforming (though I’d need to confirm that).

  • Give us actual rowgroups (not just tbody) along with colgroups in tables and maybe browsers will begin to support both of them. (Table headers also badly need fixing.)

Could you elaborate a little? What are the problems and limitations with thead, tfoot and tbody? As far as I can tell, the HTML table row group model is the same as that in Tagged PDF, so that didn’t give me any clues as to what you mean.

  • Let us nest certain block-level elements in certain other ones right away, à la XHTML 2. A p really should be able to contain an ol.

This is already allowed. However, there are backwards compatibility issues with making the DOM match in HTML (not XHTML). If browsers were to suddenly allow such elements to appear within p elements in the DOM, it could potentially break millions of pages. However, this is not an issue in XHTML 5, it is already explicitly allowed.

  • Make embed legal. Give it up, people: object doesn’t work and never will.

This already planned to be introduced, it just hasn’t made it into the spec yet.

  • Give us back dir and menu. They used to be in HTML before the W3C decided that CERN physics papers never need directories and menus.

The menu element has already been brought back. What’s the use case for dir? The HTML 2.0, 3.2 and 4.01 specs are incredibly vague on this issue and seem to only indicate presentational differences, which aren’t even visible in current browsers. How is it different from ul? What problem does it solve? What benefits does it provide?

The Cascade: Part 2 (Finally!)

Exactly one year ago from this day, I published part 1 in a series of articles about CSS cascading and inheritance. However, due to various factors (mostly laziness), the sequel never got published… Until now! Today, I’m going to take a break from the XBL series of articles (which will resume in a day or so) and finally publish the long awaited conclusion to this series. If you haven’t read part 1 (or even if did a long time ago), I suggest you do so now before continuing.

Following on from the first article in which we looked at how to find all the style declarations that applied to each element, we’re going to show how these are sorted by order of precedence, to determine which ones are applied to the element.

Sorting

Steps 2, 3 and 4 of the algorithm deal with sorting the declarations into the order of precedence. From the exercise in the part 1, we were left with 4 rule sets which applied to the p element in the sample document. For the purpose of this exercise, I’m just going to add a few more declarations and annotate them with their origin.

p { margin: 1em 0; } /* User Agent */
* { background: blue none !important; color: white !important; } /* User */
P { text-indent: 1em; text-align: left; } /* User */
p { text-align: justify; } /* User */
#content p { margin: .8em 0; line-height: 1.2; text-indent: 0 !important; } /* Author */
p { line-height: 1.4; } /* Author */

Step 2

Step 2 of the cascade says to sort the rules according to importance and origin. The following is the order of precedence specified in CSS 2.1.

  1. user agent declarations
  2. user normal declarations
  3. author normal declarations
  4. author important declarations
  5. user important declarations

If we discard the selectors for now (they’ll be need again in step 3 below), we’re left with a list of declarations. A declaration is a property and its associated value. We can then proceed to sort them into the order specified.

  1. User Agent Declarations
    1. margin: 1em 0;
  2. User Normal Declarations
    1. text-indent: 1em;
    2. text-align: left;
    3. text-align: justify;
  3. Author Normal Declarations
    1. margin: .8em 0;
    2. line-height: 1.2;
    3. line-height: 1.4;
  4. Author Important Declarations
    1. text-indent: 0 !important;
  5. User Important Declarations
    1. background: blue none !important;
    2. color: white !important;

Step 3

Step 3 of the cascade then says to sort the rules with the same importance and origin by the specificity of the selector. The details of calculating the specificity is out of scope for this article, but it has been covered by others. See Andy Clarke’s Specificity Wars and Molly Holzschlag’s CSS2 and CSS2.1 Specificity Clarified.

This step is important for cases where two declarations for the same property have the same importance and origin. In this example, this occurs for both user normal declarations (two text-align declarations) and author normal declarations (two line-height declarations).

For the user normal declarations, these are the rule sets involved:

p { text-indent: 1em; text-align: left; } /* User */
p { text-align: justify; } /* User */

As you can see, both have the same selector (p), which has a specificy of 0,0,1. So, sorting by specificity in this case makes no difference. However, for the author normal declarations, these are the rule sets involved:

p { line-height: 1.4; } /* Author */
#content p { margin: .8em 0; line-height: 1.2; text-indent: 0 !important; } /* Author */

These 2 rule sets each use different selectors which have different specificity. The selector #content p has a specificity of 101. The selector p has a specificity of 0,0,1. Since 1,0,1 is a higher specificity than 0,0,1, the former takes precedence. So the order of author normal declarations is changed to the following:

  1. margin: .8em 0;
  2. line-height: 1.4;
  3. line-height: 1.2;

Step 4

The forth and final step of the sorting process involves sorting declarations which have the same importance, origin and specificity by the order they are specified in the CSS. This is where the order of the user normal declarations from step 3 is resolved. In this example, given that I listed the declarations in the order in which they appeared, no change needs to be made to the above list.

In cases where there is more than one declaration for a property, the latter declaration overwrites the former, which is effectively discarded. This leaves the following list of declarations to be applied to element.

  1. text-align: justify;
  2. margin: .8em 0;
  3. line-height: 1.4;
  4. text-indent: 0;
  5. background: blue none;
  6. color: white;

This concludes the series about the cascade, but the related issue of inheritence still needs to be addressed and I intend to do so at some point in the future. However, I don’t expect that it will take another year before I do… But who knows? :-)