If the input string passed to this function and the final document share the same character set, this function is sufficient to prepare input for inclusion in most contexts of an HTML document. If, however, the input can represent characters that are not coded in the final document character set and you wish to retain those characters (as numeric or named entities), both this function and htmlentities() (which only encodes substrings that have named entity equivalents) may be insufficient. You may have to use mb_encode_numericentity() instead.
Example -
Example #1 htmlspecialchars() example
Parameter
Description
string
Required. Specifies the string to convert
flags
Optional. Specifies how to handle quotes, invalid encoding and the used document type.
The available quote styles are:
ENT_COMPAT - Default. Encodes only double quotes
ENT_QUOTES - Encodes double and single quotes
ENT_NOQUOTES - Does not encode any quotes
Invalid encoding:
ENT_IGNORE - Ignores invalid encoding instead of having the function return an empty string. Should be avoided, as it may have security implications.
ENT_SUBSTITUTE - Replaces invalid encoding for a specified character set with a Unicode Replacement Character U+FFFD (UTF-8) or FFFD; instead of returning an empty string.
ENT_DISALLOWED - Replaces code points that are invalid in the specified doctype with a Unicode Replacement Character U+FFFD (UTF-8) or FFFD;
Additional flags for specifying the used doctype:
ENT_HTML401 - Default. Handle code as HTML 4.01
ENT_HTML5 - Handle code as HTML 5
ENT_XML1 - Handle code as XML 1
ENT_XHTML - Handle code as XHTML
character-set
Optional. A string that specifies which character-set to use.
ISO-8859-15 - Western European (adds the Euro sign + French and Finnish letters missing in ISO-8859-1)
cp866 - DOS-specific Cyrillic charset
cp1251 - Windows-specific Cyrillic charset
cp1252 - Windows specific charset for Western European
KOI8-R - Russian
BIG5 - Traditional Chinese, mainly used in Taiwan
GB2312 - Simplified Chinese, national standard character set
BIG5-HKSCS - Big5 with Hong Kong extensions
Shift_JIS - Japanese
MacRoman - Character-set that was used by Mac OS
double_encode
Optional. A boolean value that specifies whether to encode existing html entities or not.
TRUE - Default. Will convert everything
FALSE - Will not encode existing html entities
The converted string.If the input string contains an invalid code unit sequence within the given encoding an empty string will be returned, unless either the ENT_IGNORE or ENT_SUBSTITUTE flags are set.