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 translations performed are:
'&' (ampersand) becomes '&'
'"' (double quote) becomes '"' when ENT_NOQUOTES is not set.
"'" (single quote) becomes ''' only when ENT_QUOTES is set.
A bitmask of one or more of the following flags, which specify how to handle quotes, invalid code unit sequences and the used document type. The default is ENT_COMPAT | ENT_HTML401.
Available flags constants
Constant Name
Description
ENT_COMPAT
Will convert double-quotes and leave single-quotes alone.
ENT_QUOTES
Will convert both double and single quotes.
ENT_NOQUOTES
Will leave both double and single quotes unconverted.
ENT_IGNORE
Silently discard invalid code unit sequences instead of returning an empty string. This is provided for backwards compatibility; avoid using it as it may have security implications.
ENT_SUBSTITUTE
Replace invalid code unit sequences with a Unicode Replacement Character U+FFFD (UTF-8) or &#FFFD; (otherwise) instead of returning an empty string.
ENT_DISALLOWED
Replace code unit sequences, which are invalid in the specified document type, with a Unicode Replacement Character U+FFFD (UTF-8) or &#FFFD; (otherwise).
ENT_HTML401
Handle code as HTML 4.01.
ENT_XML1
Handle code as XML 1.
ENT_XHTML
Handle code as XHTML.
ENT_HTML5
Handle code as HTML 5.
charset
Defines character set used in conversion. The default character set is ISO-8859-1.
For the purposes of this function, the charsets ISO-8859-1, ISO-8859-15, UTF-8, cp866, cp1251, cp1252, and KOI8-R are effectively equivalent, provided the string itself is valid for the character set, as the characters affected by htmlspecialchars() occupy the same positions in all of these charsets.
Following character sets are supported in PHP 4.3.0 and later.
Supported charsets
Charset
Aliases
Description
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.
Shift_JIS
SJIS, 932
Japanese
EUC-JP
EUCJP
Japanese
''
An empty string activates detection from script encoding (Zend multibyte), default_charset and current locale (see nl_langinfo() and setlocale()), in this order. Not recommended.
Note: Any other character sets are not recognized. The default encoding will be used instead and a warning will be emitted.
double_encode
When double_encode is turned off PHP will not encode existing html entities, the default is to convert everything.
If the input string contains an invalid code unit sequence within the given charset and the ENT_IGNORE flag is not set, then htmlspecialchars() will return an empty string.
Changelog
Version
Description
5.4.0
The constants ENT_SUBSTITUTE, ENT_DISALLOWED, ENT_HTML401, ENT_XML1, ENT_XHTML and ENT_HTML5 were added.
