Bug 17123 - Percentage values of height are not well-defined
Summary: Percentage values of height are not well-defined
Status: NEW
Alias: None
Product: CSS
Classification: Unclassified
Component: CSS Level 2 (show other bugs)
Version: unspecified
Hardware: PC Windows 3.1
: P2 normal
Target Milestone: ---
Assignee: Bert Bos
QA Contact: public-css-bugzilla
Depends on:
Reported: 2012-05-20 16:10 UTC by Anton P
Modified: 2012-12-04 00:52 UTC (History)
2 users (show)

See Also:


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Description Anton P 2012-05-20 16:10:30 UTC
Reported by Øyvind Stenhaug

10.5 (Content height: the 'height' property)
[http://www.w3.org/TR/CSS21/visudet.html#propdef-height] says:

  # <percentage>
  #   [...] If the height of the containing block is not
  #   specified explicitly (i.e., it depends on content height),
  #   and this element is not absolutely positioned, the value
  #   computes to 'auto'.

Firstly, the term "specified explicitly" seems nonsensical: on the one hand, /all/ elements have a specified value, and on the other hand, the containing block isn't an element. So the parentheses actually contain the crucial part here, and readers must figure out for themselves how exactly to determine whether the containing block depends on content height.

Secondly, to what does "the height" refer?
- The so-called tentative used height?
- The used value?
- Something else?

Relevant examples:

a) display: table-cell; height: 0;

Computed value of 'height' is not 'auto', but used value of 'height' still depends on the content...

b) position: absolute; top: 0; bottom: 0; height: auto;

Computed value of 'height' is 'auto', but used value of 'height' does not depend on the content.

Conversation begins: http://lists.w3.org/Archives/Public/www-style/2012Jan/1176.html

Bug description: