Domain Names.

Numerous domain name authorities already offer internationalized domain names. These include providers for such large domains as .cn, .jp, .kr, and many more.

One of the problems associated with IDN support in browsers is that it can facilitate phishing. Consequently, most browsers that support IDN also put in place some safeguards to protect users from such fraud.
Another problem is that Internet Explorer 6, with its huge market share, does not natively support IDN [though plugins are available]. However, IE7, which does support IDN, will, over time, replace most IE6 installs.

Note, that as a temporary fallback solution, until IDN is more widely supported, content authors who want to point to a resource using an IDN can write the link text in native characters, but put a punycode representation in the href attribute. Though not an ideal solution, it would guarantee that the user would be able to link to the resource, whatever platform they used.

You can run a basic check to see whether it works on your system using this simple test.

Here's a look at how some browsers support IDN:

1. Internet Explorer 7
• Looks at the languages selected in the browser preferences, and from that deduces a set of scripts for which to fully enable IDN
• If ASCII is mixed with any one of the following scripts, the URL is displayed in Unicode [provided the appropriate browser language preferences have been set]:
  
  • Arab (Arabic)
  • Bali (Balinese)
  • Beng (Bengali)
  • Bugi (Buginese)
  • Deva (Devanagari)
  • Ethi (Ethiopic)
  • Gujr (Gujarati)
  • Guru (Gurmukhi)
  • Hang (Hangul)
  • Hani (Han)
  • Hebr (Hebrew)
  • Hira (Hiragana)
  • Kana (Katakana)
  • Khmr (Khmer)
  • Knda (Kannada)
  • Laoo (Lao)
  • Mlym (Malayalam)
  • Mong (Mongolian)
  • Mymr (Myanmar)
  • Orya (Oriya)
  • Sinh (Sinhala)
  • Syrc (Syriac)
  • Taml (Tamil)
  • Telu (Telugu)
  • Thaa (Thaana)
  • Thai (Thai)
  • Tibt (Tibetan)
  
  
• Uses punycode to display a domain name if any one of the following conditions is met:
  • The domain name contains characters which are not a part of any script
  • A single domain label mixes characters that are not contained in any single script [except when mixing ASCII and one of the above scripts]
  • The domain name contains a character from a language not included in the user's language preferences
• If punycode is displayed, then so is the yellow Information Bar
• Allows IDN disabling
• Uses an icon at the end of the address bar to notify you when an URL contains a non-ASCII character
2. Internet Explorer 6
   • By default does not support IDN at all
   • 3^rd party plugins are available which provide IDN support
3. Firefox 2.x
   • Handles IDNs mainly based on the URLs top-level-domain [TLD - .com, .de, .jp etc.]
   • Some TLDs are trusted, while others are not. IDNs within trusted TLDs are displayed properly, while those not within trusted TLDs are displayed as punycode
   • IDN support can be switched off entirely by setting the network.enableIDN preference to false, in the about:config page
   • IDNs that contain particular characters [e.g. fraction-slash], even within trusted TLDs, are treated suspiciously, and are displayed as punycode
   • See Mozilla.org's policy on IDN-enabled TLDs
4. Mozilla 1.7x
   • Supports IDN
   • Displays all IDN URLs as punycode
   • IDN support can be switched off entirely by setting the network.enableIDN preference to false, in the about:config page
5. Opera 9.1
   • Supports IDN
   • Uses a whitelist of TLDs for which to allow proper display of IDNs
   • However, even for some trusted TLDs, it will still display IDNs as punycode, if any label mixes certain scripts
   • Opera's list of illegal characters is slightly longer than the official IDNA list. Some IDNs, while displayed as punycode in other browsers, are entirely illegal in Opera

Examples:

Note: For an explanation of a browser's behavior for a particular IDN, please 'mouseover' the text in the browser's column.