(PHP 4, PHP 5)
htmlspecialchars — Convert special characters to HTML entities
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:
The string being converted.
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.
| 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. |
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.
| 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.
When double_encode is turned off PHP will not encode existing html entities, the default is to convert everything.
The converted string.
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.
| Version | Description |
|---|---|
| 5.4.0 | The constants ENT_SUBSTITUTE, ENT_DISALLOWED, ENT_HTML401, ENT_XML1, ENT_XHTML and ENT_HTML5 were added. |
| 5.3.0 | The constant ENT_IGNORE was added. |
| 5.2.3 | The double_encode parameter was added. |
| 4.1.0 | The charset parameter was added. |
Example #1 htmlspecialchars() example
<?php
$new = htmlspecialchars("<a href='test'>Test</a>", ENT_QUOTES);
echo $new; // <a href='test'>Test</a>
?>
Note:
Note that this function does not translate anything beyond what is listed above. For full entity translation, see htmlentities().