Certain characters have special significance in HTML, and should be represented by HTML entities if they are to preserve their meanings. This function returns a string with some of these conversions made; the translations made are those most useful for everyday web programming. If you require all HTML character entities to be translated, use htmlentities() instead.
This function is useful in preventing user-supplied text from containing HTML markup, such as in a message board or guest book application. The optional second argument, quote_style, tells the function what to do with single and double quote characters. The default mode, ENT_COMPAT, is the backwards compatible mode which only translates the double-quote character and leaves the single-quote untranslated. If ENT_QUOTES is set, both single and double quotes are translated and if ENT_NOQUOTES is set neither single nor double quotes are translated.
The translations performed are:
'&' (ampersand) becomes '&'
'"' (double quote) becomes '"' when ENT_NOQUOTES is not set.
''' (single quote) becomes ''' only when ENT_QUOTES is set.
'<' (less than) becomes '<'
'>' (greater than) becomes '>'
Note that this function does not translate anything beyond what is listed above. For full entity translation, see htmlentities(). Support for the optional second argument was added in PHP 3.0.17 and PHP 4.0.3.
The third argument charset defines character set used in conversion. The default character set is ISO-8859-1. Support for this third argument was added in PHP 4.1.0.
Following character sets are supported in PHP 4.3.0 and later.
Table 1. Supported charsets
|ISO-8859-1||ISO8859-1||Western European, Latin-1|
|ISO-8859-15||ISO8859-15||Western European, Latin-9. Adds the Euro sign, French and Finnish letters missing in Latin-1(ISO-8859-1).|
|UTF-8||ASCII compatible multi-byte 8-bit Unicode.|
|cp866||ibm866, 866||DOS-specific Cyrillic charset. This charset is supported in 4.3.2.|
|cp1251||Windows-1251, win-1251, 1251||Windows-specific Cyrillic charset. This charset is supported in 4.3.2.|
|cp1252||Windows-1252, 1252||Windows specific charset for Western European.|
|KOI8-R||koi8-ru, koi8r||Russian. This charset is supported in 4.3.2.|
|BIG5||950||Traditional Chinese, mainly used in Taiwan.|
|GB2312||936||Simplified Chinese, national standard character set.|
|BIG5-HKSCS||Big5 with Hong Kong extensions, Traditional Chinese.|
Note: Any other character sets are not recognized and ISO-8859-1 will be used instead.