Browser IDN display policy: opinions sought

Michel Suignard michel at
Wed Dec 14 19:12:21 CET 2011

> I looked at http://www.viagé in IE (IE8 on Win7),
> and it showed punycode. I then added "en" (English) to my
> language preferences (which were just "ja" (Japanese)
> out of the box because I rarely use IE). 
>viagénie was still shown in punycode. Then I added "de" 
>(German), and now viagénie was shown. So either IE uses
> a separate "script" category "ASCII-only" (but the algorithm
> would still be script-oriented at the core) or the letters for
> a language are taken rather widely, with German including
> French accented letters and so on (which would be a
> language-only algorithm).
>Michel, if you know any details (that you can talk about),
> it would be nice to hear from you.

Martin, you are correct, enabling any Latin based languages other than English would unlock IDN for Latin script in IE. I was never a fan of blocking IDN for English users but I was not part of the IE team and that was their decision. Given that new devices are able to show most U-label w/o install of new fonts I agree that nowadays browsers should show them. And being in charge of creating charts for all of them in both Unicode and 10646 I can tell it is not a small feast.

I also found some public information about the white list that IE uses for script mixing. It is a bit old (2006), but I don't think it has changed but I obviously don't know. Check 


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