[whatwg] strong and em difference not clear

Rikkert Koppes lists at rikkertkoppes.com
Sun Feb 22 09:45:25 PST 2009

Maybe the terms "global emphasis" and "local emphasis" could help. In 
printed media bold and italic print behave differently in the sense that 
bold words grab attention directly, since it is based on lightness 
difference, for which the entire retina is highly sensitive, whereas 
italic words only grab attention when looked at, since it is based on 
differences in orientation, for which the fovea is much more sensitive.

Hence, bold words have meaning with regard to the entire document and 
italic words have meaning just for the sentence read at the moment.

Although the em and strong elements are deliberately detached from their 
appearance, the emerging semantics (global and local emphasis) still 
make sense. Note that from a perception point of view, global emphasis 
may also be achieved by other means for which the entire retina is 
sensitive. Difference in color for example. Local emphasis may also be 
achieved by changing font. [1,2]

[1] http://en.wikipedia.org/wiki/Emphasis_(typography)
[2] http://www.cs.tut.fi/~jkorpela/html/em.html

Rikkert Koppes

Peter Michaux wrote:
> On Tue, Feb 17, 2009 at 12:45 PM, Edward O'Connor <hober0 at gmail.com> wrote:
>>> The HTML 5 spec doesn't give clear guidance on the choice between
>>> strong and em tags.
>> The spec distinguishes between importance (<strong>) and emphasis
>> (<em>) like so:
>> "The placement of emphasis changes the meaning of the sentence. The
>> element thus forms an integral part of the content."
>> and
>> "Changing the importance of a piece of text with the strong element
>> does not change the meaning of the sentence."
>> So, basically, putting <em> around different words in a sentence
>> changes the sentence's meaning, whereas moving <strong> around in the
>> same way doesn't alter the meaning of the text.
>> Do you think that's sufficiently clear?
> I suppose it is reasonably clear with these two sentences. I should
> have attributed more attention to them.
> Thank you,
> Peter

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