PHP: htmlspecialchars function - Convert special characters to HTML entities

Description

string htmlspecialchars ( string $string [, int $quote_style [, string $charset [, bool $double_encode ]]] )

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.
'<' (less than) becomes '<'
'>' (greater than) becomes '>'

Parameters

string

The string being converted.

quote_style

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.

charset

Defines character set used in conversion. The default character set is ISO-8859-1.

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

Note: Any other character sets are not recognized and ISO-8859-1 will be used instead.

double_encode

When double_encode is turned off PHP will not encode existing html entities, the default is to convert everything.

Return Values

The converted string.

ChangeLog

Version	Description
5.2.3	The `double_encode` parameter was added.
4.1.0	The `charset` parameter was added.

Examples

Example #1 htmlspecialchars() example


<?php
$new = htmlspecialchars("<a href='test'>Test</a>", ENT_QUOTES);
echo $new; // &lt;a href=&#039;test&#039;&gt;Test&lt;/a&gt;
?>

Notes

Note: Note that this function does not translate anything beyond what is listed above. For full entity translation, see htmlentities().

htmlspecialchars