htmlspecialchars

Parameters

string

The string being converted.

flags

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. Using this flag is discouraged as it » may have security implications.
ENT_SUBSTITUTE	Replace invalid code unit sequences with a Unicode Replacement Character U+FFFD (UTF-8) or � (otherwise) instead of returning an empty string.
ENT_DISALLOWED	Replace invalid code points for the given document type with a Unicode Replacement Character U+FFFD (UTF-8) or � (otherwise) instead of leaving them as is. This may be useful, for instance, to ensure the well-formedness of XML documents with embedded external content.
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.

encoding

An optional argument defining the encoding used when converting characters.

If omitted, the default value of the encoding varies depending on the PHP version in use. In PHP 5.6 and later, the default_charset configuration option is used as the default value. PHP 5.4 and 5.5 will use UTF-8 as the default. Earlier versions of PHP use ISO-8859-1.

Although this argument is technically optional, you are highly encouraged to specify the correct value for your code if you are using PHP 5.5 or earlier, or if your default_charset configuration option may be set incorrectly for the given input.

For the purposes of this function, the encodings 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 encoding, as the characters affected by htmlspecialchars occupy the same positions in all of these encodings.

The following character sets are supported:

Supported charsets

Charset	Aliases	Description
ISO-8859-1	ISO8859-1	Western European, Latin-1.
ISO-8859-5	ISO8859-5	Little used cyrillic charset (Latin/Cyrillic).
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.
cp1251	Windows-1251, win-1251, 1251	Windows-specific Cyrillic charset.
cp1252	Windows-1252, 1252	Windows specific charset for Western European.
KOI8-R	koi8-ru, koi8r	Russian.
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, SJIS-win, cp932, 932	Japanese
EUC-JP	EUCJP, eucJP-win	Japanese
MacRoman		Charset that was used by Mac OS.
''		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.