117笔记问答在PHP中，mb_str函数支持以下编码格式：
- UTF-8
- ASCII
- ISO-8859-1 (Latin1)
- ISO-8859-2 (Latin2)
- ISO-8859-3 (Latin3)
- ISO-8859-4 (Latin4)
- ISO-8859-5 (Cyrillic)
- ISO-8859-6 (Arabic)
- ISO-8859-7 (Greek)
- ISO-8859-8 (Hebrew)
- ISO-8859-9 (Latin5)
- ISO-8859-10 (Latin6)
- ISO-8859-13 (Latin7)
- ISO-8859-14 (Latin8)
- ISO-8859-15 (Latin9)
- ISO-8859-16 (Latin10)
- Windows-1251 (Cyrillic)
- Windows-1252 (Latin1)
- Windows-1254 (Turkish)
- Shift JIS (Japanese)
- EUC-JP (Japanese)
- ISO-2022-JP (Japanese)
- CP932 (Japanese)
- UCS-2 (Unicode)
- UCS-4 (Unicode)
- UTF-16 (Unicode)
- UTF-32 (Unicode)
- UTF-7
- UTF-7-IMAP
- UTF-8-MAC
- UTF-8-HFS
这些编码格式可以在mb_str函数中用来处理相应的字符串。