Defining Block Level Elements

Wednesday, March 7th, 2007

I know what an HTML block level element is, but I’m damned if I can say it in a concise, correct, obvious way (which it so happens I need to do in Chapter 4 of Refactoring HTML). In HTML, block level elements include p, blockquote, div, table, ul, ol, dl, h1h6, and a few others. Generally speaking a block element has a line break before and after it, but that’s really only true in a particualr visual representation. The notion of line breaks doesn’t make a lot of sense in a screen reader, for example.

The HTML 4.0.1 specification defines block elements thusly:

Certain HTML elements that may appear in BODY are said to be “block-level” while others are “inline” (also known as “text level”). The distinction is founded on
several notions:

Content model
Generally, block-level elements may contain inline elements and other
block-level elements. Generally, inline elements may contain only data and
other inline elements. Inherent in this structural distinction is the idea that
block elements create “larger” structures than inline elements.
Formatting
By default, block-level elements are formatted differently than inline
elements. Generally, block-level elements begin on new lines, inline elements
do not. For information about white space, line breaks, and block formatting,
please consult the section on text.
Directionality
For technical reasons involving the [UNICODE] bidirectional
text algorithm, block-level and inline elements differ in how they inherit
directionality information. For details, see the section on inheritance of text direction.

That’s not a great definition though. These seem more to be consequences rather than defining characteristics of block level elements.

Can anyone offer a more precise definition of block element that does not presume a particular rendering? Just what is a block anyway?

Dawn in Santa Clara

Tuesday, March 6th, 2007

I’m just now realizing that the new earlier daylight savings time is going to play havoc with the planned Birding BoF at SD 2007 West in a couple of weeks. Sunrise isn’t going to happen till about 7:00 A.M., and I was planning to get going at 6:00.

Can anyone currently birding in Santa Clara County give me a heads up to let me know what’s the earliest you think we could reasonably start on March 21? We could push back the start time a little, but I don’t have much time before I have to get everyone back to the hotel for the 8:30 A.M. first session. Possibly instead of walking back to the hotel, we could simply bird Sunnyvale Baylands Park and then take cabs back. Here’s another question for locals: last year the park gates were open well before their scheduled opening time. Is that reliable? If we drive over, can we be confident we’ll be able to park?
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Why Are Old Cars Stolen?

Monday, March 5th, 2007

According to State Farm,

The National Insurance Crime Bureau (NICB®) has compiled a list of the 10 vehicles most frequently reported stolen in the U.S. in 2005.

  1. 1991 Honda Accord
  2. 1995 Honda Civic
  3. 1989 Toyota Camry
  4. 1994 Dodge Caravan
  5. 1994 Nissan Sentra
  6. 1997 Ford F150 Series
  7. 1990 Acura Integra
  8. 1986 Toyota Pickup
  9. 1993 Saturn SL
  10. 2004 Dodge Ram Pickup

This doesn’t match my expectations at all. With the single exception of the 2004 Dodge Ram Pickup, these are all a decade old or older. Can anyone explain why?
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Migrating Accounts

Thursday, March 1st, 2007

Mostly the Migration Assistant in Mac OS X works, but there are some surprising things that don’t come across and have to be reinstalled manually. So far I’ve noticed:
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