How to use php htmlspecialchars function

PHP htmlspecialchars function is used to convert special characters into HTML entities. Its syntax is htmlspecialchars(string,flags,character-set,double_encode). The parameter string is required and refers to the string to be converted.

php How to use the htmlspecialchars function?

php htmlspecialchars() function syntax

Function: The function converts predefined characters into HTML entities. The predefined characters are: & (ampere) becomes &, " (double quote) becomes ", ' (single quote) becomes ', < (less than) becomes <, > (greater than) becomes >.

Syntax:

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

Parameters:

string Required, specifies the string to be converted.

flagsOptional. Specifies how to handle quotes, invalid encodings, and which document type to use. Available quote types:

ENT_COMPAT - Default. Only double quotes are encoded.

ENT_QUOTES - Encodes double and single quotes.

ENT_NOQUOTES - Do not encode any quotes. Invalid encoding: ENT_IGNORE - Ignore invalid encodings instead of having the function return an empty string. This should be avoided as this may have an impact on security.

ENT_SUBSTITUTE - Substitutes an invalid encoding with the specified character with the Unicode substitution character U FFFD (UTF-8) or &#FFFD; instead of returning an empty string.

ENT_DISALLOWED - Replaces invalid code points in the specified document type with the Unicode replacement character U FFFD (UTF-8) or &#FFFD;. Additional flags specifying the document type to use: ENT_HTML401 - Default. Code processed as HTML 4.01. ENT_HTML5 - Process code as HTML 5. ENT_XML1 - Code processed as XML 1. ENT_XHTML - as XHTML processing code.

character-set Optional. A string specifying the character set to be used. Allowed values: UTF-8 - Default. ASCII compatible multibyte 8-bit Unicode ISO-8859-1 - Western Europe ISO-8859-15 - Western Europe (adds French and Finnish letters missing from ISO-8859-1 for Euro symbol) cp866 - DOS-specific Cyrillic character set cp1251 - Windows Special Cyrillic character set cp1252 - Windows special Western European character set KOI8-R - Russian BIG5 - Traditional Chinese, mainly used in Taiwan, GB2312 - Simplified Chinese, national standard character set, BIG5-HKSCS - Big5 with Hong Kong extension, Shift_JIS - Japanese, EUC-JP - Japanese, MacRoman - the character set used by the Mac operating system. In versions prior to PHP 5.4, unrecognized character sets will be ignored and replaced by ISO-8859-1. As of PHP 5.4, unrecognized character sets are ignored and replaced by UTF-8.

double_encode Optional, Boolean value, specifies whether to encode existing HTML entities. TRUE - Default. Each entity will be converted. FALSE - Existing HTML entities will not be encoded.

Description:

Returns the converted string. If string contains an invalid encoding, an empty string is returned unless the ENT_IGNORE or ENT_SUBSTITUTE flag is set.

php htmlspecialchars() function usage example 1:

<?php
$i = "<script>alert(&#39;hello world&#39;)</script>";
$j = htmlspecialchars($i);
echo $j;
?>

Output:

<script>alert(&#39;hello world&#39;)</script>

php htmlspecialchars() function usage example 2:

<?php
$new = htmlspecialchars("<a href=&#39;test&#39;>Test</a>", ENT_QUOTES);
echo $new; // <a href=&#39;test&#39;>Test</a>
?>

Output:

<a href=&#39;test&#39;>Test</a>

This article is an introduction to the PHP htmlspecialchars function. I hope it will be helpful to friends in need!

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