Latest web development tutorials
 

PHP htmlspecialchars() Function

< PHP String Reference

Example

Convert the predefined characters "<" (less than) and ">" (greater than) to HTML entities:

<?php
$str = "This is some <b>bold</b> text.";
echo htmlspecialchars($str);
?>

The HTML output of the code above will be (View Source):

<!DOCTYPE html>
<html>
<body>
This is some &lt;b&gt;bold&lt;/b&gt; text.
</body>
</html>

The browser output of the code above will be:

This is some <b>bold</b> text.
Run example »

Definition and Usage

The htmlspecialchars() function converts some predefined characters to HTML entities.

The predefined characters are:

  • & (ampersand) becomes &amp;
  • " (double quote) becomes &quot;
  • ' (single quote) becomes &#039;
  • < (less than) becomes &lt;
  • > (greater than) becomes &gt;

Tip: To convert special HTML entities back to characters, use the htmlspecialchars_decode() function.


Syntax

htmlspecialchars(string,flags,character-set,double_encode)

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.

Allowed values are:

  • UTF-8 - Default. ASCII compatible multi-byte 8-bit Unicode
  • ISO-8859-1 - Western European
  • 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
  • EUC-JP - Japanese
  • MacRoman - Character-set that was used by Mac OS

Note: Unrecognized character-sets will be ignored and replaced by ISO-8859-1 in versions prior to PHP 5.4. As of PHP 5.4, it will be ignored an replaced by UTF-8.

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

Technical Details

Return Value: Returns the converted string

If the string contains invalid encoding, it will return an empty string, unless either the ENT_IGNORE or ENT_SUBSTITUTE flags are set
PHP Version: 4+
Changelog: The default value for the character-set parameter was changed to UTF-8 in PHP 5

ENT_SUBSTITUTE, ENT_DISALLOWED, ENT_HTML401, ENT_HTML5, ENT_XML1 and ENT_XHTML were added in PHP 5.4

ENT_IGNORE was added in PHP 5.3

The double_encode parameter was added in PHP 5.2.3

The character-set parameter was added in PHP 4.1

More Examples

Example 1

Convert some predefined characters to HTML entities:

<?php
$str = "Jane & 'Tarzan'";
echo htmlspecialchars($str, ENT_COMPAT); // Will only convert double quotes
echo "<br>";
echo htmlspecialchars($str, ENT_QUOTES); // Converts double and single quotes
echo "<br>";
echo htmlspecialchars($str, ENT_NOQUOTES); // Does not convert any quotes
?>

The HTML output of the code above will be (View Source):

<!DOCTYPE html>
<html>
<body>
Jane &amp; 'Tarzan'<br>
Jane &amp; &#039;Tarzan&#039;<br>
Jane &amp; 'Tarzan'
</body>
</html>

The browser output of the code above will be:

Jane & 'Tarzan'
Jane & 'Tarzan'
Jane & 'Tarzan'
Run example »

Example 2

Convert double quotes to HTML entities:

<?php
$str = 'I love "PHP".';
echo htmlspecialchars($str, ENT_QUOTES); // Converts double and single quotes
?>

The HTML output of the code above will be (View Source):

<!DOCTYPE html>
<html>
<body>
I love &quot;PHP&quot;.
</body>
</html>

The browser output of the code above will be:

I love "PHP".
Run example »

< PHP String Reference