[whatwg] A tag for measurements / quantity?

Max Romantschuk max at romantschuk.fi
Tue Aug 18 23:50:34 PDT 2009

Aryeh Gregor wrote:
> It's not very hard to auto-convert units without semantic markup.  I'd
> think it would be pretty easy to write a browser extension that read
> through a site's HTML and converted the units without author support.
> This would have the major advantage of not relying on authors knowing
> how to mark up their document correctly, so it would work in all cases
> instead of in probably a small minority.  Has anyone written such an
> extension?

There is an extension:

Judging from the documentation it seems to work rather well with trivial 

But there are a number of situations where semantic information could 
aid conversion. For example Finnish has a rather complex morphology 
which makes automatic conversion tricky. The units will not be parseable 
from the text without parsing the language grammar.

An example:
Lisää 1 teelusikallinen sokeria 2 desilitraan vettä.
Add 1 teaspoon of sugar to 2 deciliters of water.

The roots of the words are 'teelusikka' and 'desilitra'.

But it's still quite possible authors would not use semantic markup even 
if it was available. Additionally there are localization issues, things 
like decimal separators and such.

It might well be such a tag would end up being used so little that 
automatic conversion would be the only viable option anyway.


        Max Romantschuk
        max at romantschuk.fi

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