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Initial Containing Block?

From: Garrett Smith <dhtmlkitchen@gmail.com>
Date: Mon, 25 Feb 2008 11:10:28 -0800
Message-ID: <c9e12660802251110r5a15dc42y738b1498a8de6f4d@mail.gmail.com>
To: "www-style@w3.org" <www-style@w3.org>

Does the initial containing block include the scrollbars?

for example

 +-----------------------------------------+-+
 |                                         | |
 |                                         |s|
 |                                         |c|
 |                                         |r|
 |                                         |o|
 |                                         |l|
 |                                         |l|
 |                                         |b|
 |                                         |a|
 |                                         |r|
 |                                         | |
 +-----------------------------------------+-+

This document ---

http://lists.w3.org/Archives/Public/www-archive/2007Aug/att-0003/offset-mess.htm
---Compares viewport height to height of ICB.

Excerpt --
"DOCUMENTATION

vh = viewport height
ICB h = initial containing block height

The information above is only about clientHeight, offsetHeight and
scrollHeight in various situations.

http://tc.labs.opera.com/tools/cssom/layout-dom-attributes has been used for
obtaining the results."

--- End.

The w3c says:
"# The containing block in which the root element lives is a rectangle
with the dimensions of the viewport, anchored at the canvas origin for
continuous media, and the page area for paged media. This containing
block is called the initial containing block. The 'direction' property
of the initial containing block is the same as for the root element. "

http://www.w3.org/TR/CSS21/visudet.html#containing-block-details

The w3c says the ICB has the same dimensions as the viewport, while
the document above compares the dimensions of the ICB to the viewport.

To me, it seems impossible to notice a comparative difference between
[anything] and itself.

I posted the definition of the ICB on the weblog, but the comment I
posted became deleted with no explanation. The misleading testcase was
removed, too.

Can David or someone clarify -
What is the Initial Containing Block in relation to the viewport?
Does it include scrollbars?

How are the dimensions of the ICB calculated? The table from the blog
make assertions of it's dimensions and also the dimensions of the
viewport. What is this based on?

Thank you,

Garrett
Received on Monday, 25 February 2008 19:10:49 GMT

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