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html_entity_decode

(PHP 4 >= 4.3.0, PHP 5)

html_entity_decode --  Convert all HTML entities to their applicable characters

Description

string html_entity_decode ( string string [, int quote_style [, string charset]] )

html_entity_decode() is the opposite of htmlentities() in that it converts all HTML entities to their applicable characters from string.

The optional second quote_style parameter lets you define what will be done with 'single' and "double" quotes. It takes on one of three constants with the default being ENT_COMPAT:

表格 1. Available quote_style constants

Constant NameDescription
ENT_COMPATWill convert double-quotes and leave single-quotes alone.
ENT_QUOTESWill convert both double and single quotes.
ENT_NOQUOTESWill leave both double and single quotes unconverted.

The ISO-8859-1 character set is used as default for the optional third charset. This defines the character set used in conversion.

PHP 4.3.0 及其后续版本支持如下字符集。

表格 2. 已支持字符集

字符集别名描述
ISO-8859-1ISO8859-1 西欧，Latin-1
ISO-8859-15ISO8859-15 西欧，Latin-9。增加了 Latin-1（ISO-8859-1）中缺少的欧元符号、法国及芬兰字母。
UTF-8  ASCII 兼容多字节 8-bit Unicode。
cp866ibm866, 866 DOS-特有的 Cyrillic 字母字符集。PHP 4.3.2 开始支持该字符集。
cp1251Windows-1251, win-1251, 1251 Windows-特有的 Cyrillic 字母字符集。PHP 4.3.2 开始支持该字符集。
cp1252Windows-1252, 1252 Windows 对于西欧特有的字符集。
KOI8-Rkoi8-ru, koi8r 俄文。PHP 4.3.2 开始支持该字符集。
BIG5950 繁体中文，主要用于中国台湾。
GB2312936 简体中文，国际标准字符集。
BIG5-HKSCS  繁体中文，Big5 的延伸，主要用于香港。
Shift_JISSJIS, 932 日文。
EUC-JPEUCJP 日文。

注: ISO-8859-1 将代替任何其它无法识别的字符集。

注: This function doesn't support multi-byte character sets in PHP < 5.

例子 1. Decoding HTML entities

<?php
$orig = "I'll \"walk\" the <b>dog</b> now";

$a = htmlentities($orig);

$b = html_entity_decode($a);

echo $a; // I'll &quot;walk&quot; the &lt;b&gt;dog&lt;/b&gt; now

echo $b; // I'll "walk" the <b>dog</b> now


// For users prior to PHP 4.3.0 you may do this:
function unhtmlentities($string)
{
    // replace numeric entities
    $string = preg_replace('~&#x([0-9a-f]+);~ei', 'chr(hexdec("\\1"))', $string);
    $string = preg_replace('~&#([0-9]+);~e', 'chr(\\1)', $string);
    // replace literal entities
    $trans_tbl = get_html_translation_table(HTML_ENTITIES);
    $trans_tbl = array_flip($trans_tbl);
    return strtr($string, $trans_tbl);
}

$c = unhtmlentities($a);

echo $c; // I'll "walk" the <b>dog</b> now

?>

注: You might wonder why trim(html_entity_decode('&nbsp;')); doesn't reduce the string to an empty string, that's because the '&nbsp;' entity is not ASCII code 32 (which is stripped by trim()) but ASCII code 160 (0xa0) in the default ISO 8859-1 characterset.

See also htmlentities(), htmlspecialchars(), get_html_translation_table(), and urldecode().


add a note add a note User Contributed Notes
nycolhas at hotmail dot com
06-Apr-2006 02:24
This function might be useful for people who want to capitalize a string using html entities.

<?php
function htmlstrtoupper(&$string) {
   return htmlentities(strtoupper(html_entity_decode(&$string)));
}
?>
buraks78 at gmail dot com
08-Feb-2006 07:19
The "unhtmlentities" function defined above fails to decode single quotes properly. The issue can be solved by putting double quotes around replacing chr(\\1) with chr("\\1")...

function unhtmlentities($string)
{
   // replace numeric entities
   $string = preg_replace('~&#x([0-9a-f]+);~ei', 'chr(hexdec("\\1"))', $string);
   $string = preg_replace('~&#([0-9]+);~e', 'chr("\\1")', $string);
   // replace literal entities
   $trans_tbl = get_html_translation_table(HTML_ENTITIES);
   $trans_tbl = array_flip($trans_tbl);
   return strtr($string, $trans_tbl);
}
hurricane at cyberworldz dot org
23-Dec-2005 12:33
I shortened the function repace_num_entity a bit to make more understandable and clean. Maybe now someone sees the problem it possibly has... (as mentioned below)

<?php
function replace_num_entity($ord) {
   $ord = $ord[1];
   if (preg_match('/^x([0-9a-f]+)$/i', $ord, $match)) $ord = hexdec($match[1]);
       else $ord = intval($ord);
   $no_bytes = 0;
   $byte = array();
   if ($ord < 128) return chr($ord);
   if ($ord < 2048) $no_bytes = 2;
       else if ($ord < 65536) $no_bytes = 3;
       else if ($ord < 1114112) $no_bytes = 4;
       else return;
   switch($no_bytes) {
       case 2: $prefix = array(31, 192); break;
       case 3: $prefix = array(15, 224); break;
       case 4: $prefix = array(7, 240);
   }
   for ($i=0; $i < $no_bytes; ++$i)
       $byte[$no_bytes-$i-1] = (($ord & (63 * pow(2,6*$i))) / pow(2,6*$i)) & 63 | 128;
   $byte[0] = ($byte[0] & $prefix[0]) | $prefix[1];
   $ret = '';
   for ($i=0; $i < $no_bytes; ++$i) $ret .= chr($byte[$i]);
   return $ret;
}
?>
loufoque
09-Oct-2005 04:15
If you want to decode NCRs to utf-8 use this function instead of chr().

function utf8_chr($code)
{
   if($code<128) return chr($code);
   else if($code<2048) return chr(($code>>6)+192).chr(($code&63)+128);
   else if($code<65536) return chr(($code>>12)+224).chr((($code>>6)&63)+128).chr(($code&63)+128);
   else if($code<2097152) return chr($code>>18+240).chr((($code>>12)&63)+128)
                                 .chr(($code>>6)&63+128).chr($code&63+128));
}
emilianomartinezluque at yahoo dot com
26-Sep-2005 08:22
I've been using the great replace_num_entity function posted below. But there seems to be some problems with the 128 to 160 characters range. Ie, try:

<?php header("Content-type: text/html; charset=utf-8"); ?>
<html><body>
<?php
for($x=128; $x<161; $x++) {
     echo('&#' . $x . '; -- ' . preg_replace_callback('/&#([0-9a-fx]+);/mi', 'replace_num_entity', '&#' . $x . ';') . '</br>');
}
?>
</body></html>

I really dont know the reason for this (since according to UTF-8 specs the function should have worked) but I did a modified version of the function to address this. Hope it helps.

function replace_num_entity($ord)
   {
       $ord = $ord[1];
       if (preg_match('/^x([0-9a-f]+)$/i', $ord, $match))
       {
           $ord = hexdec($match[1]);
       }
       else
       {
           $ord = intval($ord);
       }
    
       $no_bytes = 0;
       $byte = array();

       if($ord == 128) {
           return chr(226).chr(130).chr(172);
       } elseif($ord == 129) {
           return chr(239).chr(191).chr(189);
       } elseif($ord == 130) {
           return chr(226).chr(128).chr(154);
       } elseif($ord == 131) {
           return chr(198).chr(146);
       } elseif($ord == 132) {
           return chr(226).chr(128).chr(158);
       } elseif($ord == 133) {
           return chr(226).chr(128).chr(166);
       } elseif($ord == 134) {
           return chr(226).chr(128).chr(160);
       } elseif($ord == 135) {
           return chr(226).chr(128).chr(161);
       } elseif($ord == 136) {
           return chr(203).chr(134);
       } elseif($ord == 137) {
           return chr(226).chr(128).chr(176);
       } elseif($ord == 138) {
           return chr(197).chr(160);
       } elseif($ord == 139) {
           return chr(226).chr(128).chr(185);
       } elseif($ord == 140) {
           return chr(197).chr(146);
       } elseif($ord == 141) {
           return chr(239).chr(191).chr(189);
       } elseif($ord == 142) {
           return chr(197).chr(189);
       } elseif($ord == 143) {
           return chr(239).chr(191).chr(189);
       } elseif($ord == 144) {
           return chr(239).chr(191).chr(189);
       } elseif($ord == 145) {
           return chr(226).chr(128).chr(152);
       } elseif($ord == 146) {
           return chr(226).chr(128).chr(153);
       } elseif($ord == 147) {
           return chr(226).chr(128).chr(156);
       } elseif($ord == 148) {
           return chr(226).chr(128).chr(157);
       } elseif($ord == 149) {
           return chr(226).chr(128).chr(162);
       } elseif($ord == 150) {
           return chr(226).chr(128).chr(147);
       } elseif($ord == 151) {
           return chr(226).chr(128).chr(148);
       } elseif($ord == 152) {
           return chr(203).chr(156);
       } elseif($ord == 153) {
           return chr(226).chr(132).chr(162);
       } elseif($ord == 154) {
           return chr(197).chr(161);
       } elseif($ord == 155) {
           return chr(226).chr(128).chr(186);
       } elseif($ord == 156) {
           return chr(197).chr(147);
       } elseif($ord == 157) {
           return chr(239).chr(191).chr(189);
       } elseif($ord == 158) {
           return chr(197).chr(190);
       } elseif($ord == 159) {
           return chr(197).chr(184);
       } elseif($ord == 160) {
           return chr(194).chr(160);
       }

       if ($ord < 128)
       {
           return chr($ord);
       }
       elseif ($ord < 2048)
       {
           $no_bytes = 2;
       }
       elseif ($ord < 65536)
       {
           $no_bytes = 3;
       }
       elseif ($ord < 1114112)
       {
           $no_bytes = 4;
       }
       else
       {
           return;
       }

       switch($no_bytes)
       {
           case 2:
           {
               $prefix = array(31, 192);
               break;
           }
           case 3:
           {
               $prefix = array(15, 224);
               break;
           }
           case 4:
           {
               $prefix = array(7, 240);
           }
       }

       for ($i = 0; $i < $no_bytes; $i++)
       {
           $byte[$no_bytes - $i - 1] = (($ord & (63 * pow(2, 6 * $i))) / pow(2, 6 * $i)) & 63 | 128;
       }

       $byte[0] = ($byte[0] & $prefix[0]) | $prefix[1];

       $ret = '';
       for ($i = 0; $i < $no_bytes; $i++)
       {
           $ret .= chr($byte[$i]);
       }

       return $ret;
   }
florianborn (at) yahoo (dot) de
20-Jul-2005 06:43
Note that

<?php

 echo urlencode(html_entity_decode("&nbsp;"));

?>

will output "%A0" instead of "+".
gaui at gaui dot is
05-Jul-2005 08:15
if( !function_exists( 'html_entity_decode' ) )
{
   function html_entity_decode( $given_html, $quote_style = ENT_QUOTES ) {
       $trans_table = array_flip(get_html_translation_table( HTML_SPECIALCHARS, $quote_style ));
       $trans_table['&#39;'] = "'";
       return ( strtr( $given_html, $trans_table ) );
       }
}
marius (at) hot (dot) ee
08-Apr-2005 09:40
To convert html entities into unicode characters, use the following:

       $trans_tbl = get_html_translation_table(HTML_ENTITIES);
       foreach($trans_tbl as $k => $v)
       {
           $ttr[$v] = utf8_encode($k);
       }
  
       $text = strtr($text, $ttr);
php dot net at c dash ovidiu dot tk
18-Mar-2005 04:37
Quick & dirty code that translates numeric entities to UTF-8.

<?php

   function replace_num_entity($ord)
   {
       $ord = $ord[1];
       if (preg_match('/^x([0-9a-f]+)$/i', $ord, $match))
       {
           $ord = hexdec($match[1]);
       }
       else
       {
           $ord = intval($ord);
       }
      
       $no_bytes = 0;
       $byte = array();

       if ($ord < 128)
       {
           return chr($ord);
       }
       elseif ($ord < 2048)
       {
           $no_bytes = 2;
       }
       elseif ($ord < 65536)
       {
           $no_bytes = 3;
       }
       elseif ($ord < 1114112)
       {
           $no_bytes = 4;
       }
       else
       {
           return;
       }

       switch($no_bytes)
       {
           case 2:
           {
               $prefix = array(31, 192);
               break;
           }
           case 3:
           {
               $prefix = array(15, 224);
               break;
           }
           case 4:
           {
               $prefix = array(7, 240);
           }
       }

       for ($i = 0; $i < $no_bytes; $i++)
       {
           $byte[$no_bytes - $i - 1] = (($ord & (63 * pow(2, 6 * $i))) / pow(2, 6 * $i)) & 63 | 128;
       }

       $byte[0] = ($byte[0] & $prefix[0]) | $prefix[1];

       $ret = '';
       for ($i = 0; $i < $no_bytes; $i++)
       {
           $ret .= chr($byte[$i]);
       }

       return $ret;
   }

   $test = 'This is a &#269;&#x5d0; test&#39;';

   echo $test . "<br />\n";
   echo preg_replace_callback('/&#([0-9a-fx]+);/mi', 'replace_num_entity', $test);

?>
Silvan
29-Jan-2005 11:33
Passing NULL or FALSE as a string will generate a '500 Internal Server Error' (or break the script when inside a function).

So always test your string first before passing it to html_entity_decode().
daniel at brightbyte dot de
14-Nov-2004 10:12
This function seems to have to have two limitations (at least in PHP 4.3.8):

a) it does not work with multibyte character codings, such as UTF-8
b) it does not decode numeric entity references

a) can be solved by using iconv to convert to ISO-8859-1, then decoding the entities, than convert to UTF-8 again. But that's quite ugly and detroys all characters not present in Latin-1.

b) can be solved rather nicely using the following code:

<?php
function decode_entities($text) {
   $text= html_entity_decode($text,ENT_QUOTES,"ISO-8859-1"); #NOTE: UTF-8 does not work!
   $text= preg_replace('/&#(\d+);/me',"chr(\\1)",$text); #decimal notation
   $text= preg_replace('/&#x([a-f0-9]+);/mei',"chr(0x\\1)",$text);  #hex notation
   return $text;
}
?>

HTH
aidan at php dot net
14-Sep-2004 03:57
This functionality is now implemented in the PEAR package PHP_Compat.

More information about using this function without upgrading your version of PHP can be found on the below link:

http://pear.php.net/package/PHP_Compat
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