htmlspecialchars()

Published Oct 28, 2023
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The htmlspecialchars() function takes a string of special characters and converts the string to HTML entities. These special characters have a specific value in HTML and need to be represented by HTML entities to preserve their meaning. The special characters and their converted HTML entities are listed in the table below:

Character Converted HTML entity
& &
"
'
< &lt;
> &gt;

Syntax

htmlspecialchars(string $string, int $flag, $string $encoding = null, bool $double_encode = true)

The htmlspecialchars() takes four parameters.

  • $string : A required parameter that specifies the string to be converted.
  • $flag : An optional string value that specifies how to handle quotes.
  • $encoding: An optional string value that specifies the character-set to use when converting characters.
  • $double_encode: An optional boolean value that specifies whether to encode existing html or not.

The available flags are listed in the table below:

Constant Description
ENT_COMPAT The default flag, it encodes only double quotes
ENT_QUOTES Encodes both double and single quotes
ENT_NOQUOTES Does not encode double nor single quotes
ENT_IGNORE Discards invalid encoding instead of the function returning an empty string
ENT_SUBSTITUTE Replaces invalid encoding with a unicode character U+FFFD (UTF-8) or &#xFFFD; instead of returning an empty string
ENT_DISALLOWED Replaces invalid code for the specified doctype with a Unicode Replacement Character U+FFFD (UTF-8) or &#FFFD;
ENT_HTML401 Handles code as HTML 4.01
ENT_HTML5 Handles code as HTML 5
ENT_XML1 Handles code as XML 1
ENT_XHTML1 Handles code as XHTML

The supported character sets are listed in the table below:

Charset Description
UTF-8 The 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: If $string contains an invalid code, the function will return an empty string unless $flag is set to ENT_IGNORE or ENT_SUBSTITUTE.

Example

The following example uses htmlspecialchars() to convert the special character & in a string to an HTML entity &amp;.

<?php
$statement ="Codecademy offers courses in various programming languages like Java, PHP, C++ & many others.";
echo htmlspecialchars($statement, ENT_COMPAT);
?>

This results in the following output:

Codecademy offers courses in various programing languages like Java, PHP, C++ &amp; many others.

Codebyte Example

The following example is runnable and uses the htmlspecialchars() function and the ENT_QUOTES flag:

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