htmlspecialchars_decode

(PHP 5 >= 5.1.0, PHP 7, PHP 8)

htmlspecialchars_decode — Wandelt besondere HTML-Entities zurück in Zeichen um

Beschreibung

htmlspecialchars_decode(string $string, int $flags = ENT_QUOTES | ENT_SUBSTITUTE | ENT_HTML401): string

Diese Funktion ist das Gegenstück zu htmlspecialchars(). Sie wandelt besondere HTML-Auszeichnungen zurück in Zeichen um.

Die umgewandelten Entities sind: &, " (wenn ENT_NOQUOTES nicht gesetzt ist), ' (wenn ENT_QUOTES gesetzt ist), < und >.

Parameter-Liste

string

Die zu dekodierende Zeichenkette.

flags

Eine Bitmaske von einem oder mehreren der folgenden Flags, die die Behandlung von Anführungszeichen sowie den zu nutzenden Dokumententyp festlegen. Der Standardwert ist ENT_QUOTES | ENT_SUBSTITUTE | ENT_HTML401.

**Verfügbare `flags`-Konstanten**
Name der Konstante	Beschreibung
`ENT_COMPAT`	Wandelt doppelte Anführungszeichen um und lässt einfache Anführungszeichen unverändert.
`ENT_QUOTES`	Wandelt sowohl doppelte als auch einfache Anführungszeichen um.
`ENT_NOQUOTES`	Lässt sowohl doppelte als auch einfache Anführungszeichen unverändert.
`ENT_SUBSTITUTE`	Ersetzt ungültige Code-Unit-Sequenzen mit dem Unicode-Ersatzzeichen U+FFFD (UTF-8) oder � (andernfalls), anstatt eine leere Zeichenkette zurückzugeben.
`ENT_HTML401`	Behandle Code als HTML 4.01.
`ENT_XML1`	Behandle Code als XML 1.
`ENT_XHTML`	Behandle Code als XHTML.
`ENT_HTML5`	Behandle Code als HTML 5.

Rückgabewerte

Gibt die dekodierte Zeichenkette zurück.

Changelog

Version	Beschreibung
8.1.0	`flags` geändert von `ENT_COMPAT` zu `ENT_QUOTES` \| `ENT_SUBSTITUTE` \| `ENT_HTML401`.

Beispiele

Beispiel #1 Ein htmlspecialchars_decode()-Beispiel

<?php
$str = "<p>this -&gt; &quot;</p>\n";

echo htmlspecialchars_decode($str);

// Beachten Sie, dass die Anführungszeichen nicht umgewandelt werden
echo htmlspecialchars_decode($str, ENT_NOQUOTES);
?>

Das oben gezeigte Beispiel erzeugt folgende Ausgabe:

<p>this -> "</p>
<p>this -> &quot;</p>

Siehe auch

htmlspecialchars() - Wandelt Sonderzeichen in HTML-Entities um
html_entity_decode() - Wandelt HTML-Entities in ihre entsprechenden Zeichen um
get_html_translation_table() - Liefert die Umwandlungstabelle, die von htmlspecialchars und htmlentities verwendet wird

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User Contributed Notes 8 notes

down

thomas at xci[ignore_this]teit dot commm ¶

16 years ago


The example for "htmlspecialchars_decode()" below sadly does not work for all PHP4 versions.

Quote from the PHP manual:
"get_html_translation_table() will return the translation table that is used internally for htmlspecialchars() and htmlentities()."

But it does NOT! At least not for PHP version 4.4.2.
This was already reported in a bug report (http://bugs.php.net/bug.php?id=25927), but it was marked as BOGUS.

Proof:
  Code:
--------------------
<?php
    var_dump(get_html_translation_table(HTML_SPECIALCHARS,ENT_QUOTES));
    var_dump(htmlspecialchars('\'',ENT_QUOTES));
?>
--------------------

  Output:
--------------------
array
  '"' => '&quot;'
  ''' => '&#39;'
  '<' => '&lt;'
  '>' => '&gt;'
  '&' => '&amp;'

'&#039;'
--------------------

This comment now is not to report this bug again (though I really believe it is one), but to complete the example and warn people of this pitfall.

To make sure your htmlspecialchars_decode fake for PHP4 works, you should do something like this:

<?php
    function htmlspecialchars_decode($string,$style=ENT_COMPAT)
    {
        $translation = array_flip(get_html_translation_table(HTML_SPECIALCHARS,$style));
        if($style === ENT_QUOTES){ $translation['&#039;'] = '\''; }
        return strtr($string,$translation);
    }
?>

Br, Thomas

down

Anonymous ¶

18 years ago


This should be the best way to do it.
(Reposted because the other one seems a bit slower and because those who used the code under called it htmlspecialchars_decode_php4)

<?php

if ( !function_exists('htmlspecialchars_decode') )
{
    function htmlspecialchars_decode($text)
    {
        return strtr($text, array_flip(get_html_translation_table(HTML_SPECIALCHARS)));
    }
}

?>

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-2

or-k at or-k dot com ¶

19 years ago


that works also with &auml; and &quot; and so on.
get_html_translation_table(HTML_ENTITIES) => offers more characters than HTML_SPECIALCHARS

function htmlspecialchars_decode_PHP4($uSTR)
{
 return strtr($uSTR, array_flip(get_html_translation_table(HTML_ENTITIES, ENT_QUOTES)));
}

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-6

pinkgothic at gmail dot com ¶

14 years ago


Keep in mind that you should never trust user input - particularly for "mixed-bag" input containing a combination of plain text and markup or scripting code.



Why?



Well, consider someone sending '&amp;<script>alert('XSS');</script>' to your PHP script:



<?php

$var = "&amp;<script>alert('XSS');</script>";

$var = (htmlspecialchars_decode($var) == $var) ? htmlspecialchars($var) : $var;

echo $var;

?>



Since '&amp;' decodes into '&', (htmlspecialchars_decode($var) == $var) will be -false-, thus returning $var without that it's escaped. In consequence, the script-tags are untouched, and you've just opened yourself to XSS.



There is, unfortunately, no reliable way to determine whether HTML is escaped or not that does not come with this caveat that I know of. Rather than try and catch the case 'I've already encoded this', you are better off avoiding double-escaping by simply escaping the HTML as close to the actual output as you can muster, e.g. in the view in an MVC development structure.

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-10

geoffers@gmail ¶

19 years ago


[Update of previous note, having noticed I forgot to put in quote style]

PHP4 Compatible function:

<?php

function htmlspecialchars_decode_php4 ($str, $quote_style = ENT_COMPAT) {
    return strtr($str, array_flip(get_html_translation_table(HTML_SPECIALCHARS, $quote_style)));
}

?>

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-12

benharold at mac dot com ¶

15 years ago


If you use `htmlspecialchars()` to change things like the ampersand (&) into it's HTML equivalent (&amp;), you might run into a situation where you mistakenly pass the same string to the function twice, resulting in things appearing on your website like, as I call it, the ampersanded amp; "&amp;". Clearly nobody want's "&amp;" on his or her web page where there is supposed to be just an ampersand. Here's a quick and easy trick to make sure this doesn't happen:

<?php

$var = "This is a string that could be passed to htmlspecialchars multiple times.";

if (htmlspecialchars_decode($var) == $var) {
    $var = htmlspecialchars($var);
}

echo $var;

?>

Now, if your dealing with text that is a mixed bag (has HTML entities and non-HTML entities) you're on your own.

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-12

benharold at mac dot com ¶

15 years ago


or of course:

<?php

$var = "Blue & yellow make green.";

$var = (htmlspecialchars_decode($var) == $var) ? htmlspecialchars($var) : $var;
echo $var; // outputs Blue &amp; yellow make green.

// you can do it a bunch of times, it still won't screw you!

$var = (htmlspecialchars_decode($var) == $var) ? htmlspecialchars($var) : $var;
$var = (htmlspecialchars_decode($var) == $var) ? htmlspecialchars($var) : $var;
echo $var; // still outputs Blue &amp; yellow make green.

?>

Put it in a function. Add it to the method of some abstract data class.

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-12

geoffers at gmail dot com ¶

19 years ago


For PHP4 Compatibility:

<?php

function htmlspecialchars_decode_php4 ($str) {
    return strtr($str, array_flip(get_html_translation_table(HTML_SPECIALCHARS)));
}

?>

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