htmlspecialchars

(PHP 4, PHP 5)

htmlspecialchars — 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 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 '>'

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;
?>

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.

PHP 4.3.0 及其后续版本支持如下字符集。

**已支持字符集**
字符集	别名	描述
ISO-8859-1	ISO8859-1	西欧，Latin-1
ISO-8859-15	ISO8859-15	西欧，Latin-9。增加了 Latin-1（ISO-8859-1）中缺少的欧元符号、法国及芬兰字母。
UTF-8		ASCII 兼容多字节 8-bit Unicode。
cp866	ibm866, 866	DOS-特有的 Cyrillic 字母字符集。PHP 4.3.2 开始支持该字符集。
cp1251	Windows-1251, win-1251, 1251	Windows-特有的 Cyrillic 字母字符集。PHP 4.3.2 开始支持该字符集。
cp1252	Windows-1252, 1252	Windows 对于西欧特有的字符集。
KOI8-R	koi8-ru, koi8r	俄文。PHP 4.3.2 开始支持该字符集。
BIG5	950	繁体中文，主要用于中国台湾。
GB2312	936	简体中文，国际标准字符集。
BIG5-HKSCS		繁体中文，Big5 的延伸，主要用于香港。
Shift_JIS	SJIS, 932	日文。
EUC-JP	EUCJP	日文。

Note: ISO-8859-1 将代替任何其它无法识别的字符集。

When double_encode is turned off PHP will not encode existing html entities, the default is to convert everything. This parameter was added in PHP 5.2.3.