The definition and usage of htmlentities() function in php-PHP Tutorial-php.cn

The definition and usage of htmlentities() function in php

墨辰丷

Release： 2023-03-29 14:08:01

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This article mainly introduces the definition and usage of the htmlentities() function in PHP. Interested friends can refer to it. I hope it will be helpful to everyone.

php htmlentities() function converts characters into HTML entities. This article introduces the basic usage and examples of the php htmlentities() function to coders. Coders in need can refer to it.

Definition and Usage

htmlentities() function converts characters into HTML entities.

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

Tip: Please use the get_html_translation_table() function to return the translation table used by htmlentities().

Grammar

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

double_encode

Parameters	Description
string	Required. Specifies the string to be converted.
flags	Optional. 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 - As XML 1 processing code. ENT_XHTML - Processing code as XHTML.
character-set	Optional. A string specifying the character set to be used. Allowed values: UTF-8 - Default. ASCII Compatible multi-byte 8-bit Unicode ##ISO-8859-1 - Western Europe ISO-8859-15 - Western Europe (joining the Euro French and Finnish letters missing from symbols ISO-8859-1) cp866 - DOS-specific Cyrillic character set cp1251 - Windows-specific Cyrillic character set cp1252 - Windows-specific Western European character set KOI8-R - Russian BIG5 - Traditional Chinese, mainly used in Taiwan GB2312 - Simplified Chinese, National Standard Character Set BIG5-HKSCS - With Hong Kong extension Big5 Shift_JIS - Japanese EUC-JP - Japanese MacRoman - Mac Operation Character set used by the system Note: 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.
	Optional. Boolean value that specifies whether to encode existing HTML entities. TRUE - Default. Each entity will be converted. FALSE - Existing HTML entities will not be encoded.

Technical details

Return value: PHP Version: 4 Change Log:

Example 1

Convert characters to HTML entities:

<?php 
$str = "Bill & &#39;Steve&#39;"; 
echo htmlentities($str, ENT_COMPAT); // 只转换双引号 
echo "<br>"; 
echo htmlentities($str, ENT_QUOTES); // 转换双引号和单引号 
echo "<br>"; 
echo htmlentities($str, ENT_NOQUOTES); // 不转换任何引号 
?>

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The HTML output of the above code is as follows (view source code):

<!DOCTYPE html> 
<html> 
<body> 
Bill & &#39;Steve&#39;<br> 
Bill & &#39;Tarzan&#39;<br> 
Bill & &#39;Steve&#39;
</body> 
</html>

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Browser output of the above code:

Bill & &#39;Steve&#39;
Bill & &#39;Steve&#39;
Bill & &#39;Steve&#39;

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Example 2

Convert some characters into HTML entities by using the Western European character set:

<?php 
$str = "My name is ?yvind ?sane. I&#39;m Norwegian."; 
echo htmlentities($str, ENT_QUOTES, "ISO-8859-1"); 
// Will only convert double quotes (not single quotes), and uses the character-set Western European 
?>

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The HTML output of the above code is as follows (view source code):

<!DOCTYPE html> 
<html> 
<body> 
My name is Øyvind Åsane. I&#39;m Norwegian. 
</body> 
</html>

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The browser output of the above code:

My name is ?yvind ?sane. I'm Norwegian.

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Return the converted string.

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

In In PHP 5, the default value of the

character-set parameter is changed to UTF-8.

In PHP 5.4, new: ENT_SUBSTITUTE, ENT_DISALLOWED, ENT_HTML401, ENT_HTML5, ENT_XML1 and ENT_XHTML.

In PHP 5.3, ENT_IGNORE is added.

In PHP 5.2.3, the

double_encode parameter was added.

In PHP 4.1, the

character-set parameter was added.

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