1. UTF-8: The Secret
of Character

2. Bert?
Web developer at Netlash
Dextro
http://dextrose.be
http://twitter.com/dextro

3. Some history... sorry
ASCII = 7 bit → 2 7 possibilities
1 byte = 8 bit → 1 bit left
parity bit
ASCII extended (ISO 8859)
Asia: DBCS

4. Unicode
NOT: 1 char = 16 bits
letter → a code point (U+234)
U+0048 U+0065 U+006C U+006C U+006F

5. Unicode memory storing
00 48 00 65 00 6C 00 6C 00 6F (little endian)
48 00 65 00 6C 00 6C 00 6F 00 (big endian)
Byte Order Mark
• FF FE (little endian)
• FE FF (big endian)

6. ways of encoding
unicode
UCS-4 (UTF-32)
high endian
low endian
UCS-2
high endian
low endian

7. ways of encoding
unicode
UTF-16: 2 or 4 bytes
UTF-8: 1, 2, 3 or 4 bytes
UTF-7: SMTP in mailtraffic

8. UTF-8
U+000 till U+127 → 1 byte
above → 2, 3, up to 6 bytes
ANSII → UTF-8 = no difference

9. UTF-8
sorting: byte oriented = sorting code
points
standard for XML (XHTML) documents
easy recognized by an algorithm

10. Sidenote
What if char is not known in the encoding?

11. In practice
Which encoding to choose?

12. Questions
Which characters am I going to use?
In which encodings can my editor save
files?
Which encodings are supported by the
various components in my publishing
chain?
Which encodings are supported by
browsers?

13. 1 character range
single language or multilanguage?
(curly) quotation marks, dashes and other
special punctuation
mathematical or other special symbols

14. 2 text editor
fixed or not?
Zend Studio for Eclipse: ISO-8859-1, US-
ASCII, UTF-16, UTF-16BE, UTF-16LE,
UTF-8

15. 3 other components
webserver
programming (or scripting) language
database
...

16. 4 browser support
no problem: US-ASCII, ISO 8859 series and
UTF-8
avoid the others (and US-ASCII...)

17. character not
available?
entity: © ë á
NCR: © or ©
more bytes
difficult to read
SEO?

18. Biggest problem
PHP5 at least
full support in PHP6