html_entity_decode

(PHP 4 >= 4.3.0, PHP 5, PHP 7, PHP 8)

html_entity_decode — Convert HTML entities to their corresponding characters

说明

html_entity_decode(string $string, int $flags = ENT_QUOTES | ENT_SUBSTITUTE | ENT_HTML401, ?string $encoding = null): string

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

More precisely, this function decodes all the entities (including all numeric entities) that a) are necessarily valid for the chosen document type — i.e., for XML, this function does not decode named entities that might be defined in some DTD — and b) whose character or characters are in the coded character set associated with the chosen encoding and are permitted in the chosen document type. All other entities are left as is.

参数

string

The input string.

flags

A bitmask of one or more of the following flags, which specify how to handle quotes and which document type to use. The default is ENT_QUOTES | ENT_SUBSTITUTE | ENT_HTML401.

**Available `flags` constants**
Constant Name	Description
`ENT_COMPAT`	Will convert double-quotes and leave single-quotes alone.
`ENT_QUOTES`	Will convert both double and single quotes.
`ENT_NOQUOTES`	Will leave both double and single quotes unconverted.
`ENT_SUBSTITUTE`	Replace invalid code unit sequences with a Unicode Replacement Character U+FFFD (UTF-8) or � (otherwise) instead of returning an empty string.
`ENT_HTML401`	Handle code as HTML 4.01.
`ENT_XML1`	Handle code as XML 1.
`ENT_XHTML`	Handle code as XHTML.
`ENT_HTML5`	Handle code as HTML 5.

encoding

An optional argument defining the encoding used when converting characters.

If omitted, encoding defaults to the value of the default_charset configuration option.

Although this argument is technically optional, you are highly encouraged to specify the correct value for your code if the default_charset configuration option may be set incorrectly for the given input.

支持以下字符集：

**支持的字符集列表**
字符集	别名	描述
ISO-8859-1	ISO8859-1	西欧，Latin-1
ISO-8859-5	ISO8859-5	Little used cyrillic charset (Latin/Cyrillic).
ISO-8859-15	ISO8859-15	西欧，Latin-9。增加欧元符号，法语和芬兰语字母在 Latin-1(ISO-8859-1) 中缺失。
UTF-8		ASCII 兼容的多字节 8 位 Unicode。
cp866	ibm866, 866	DOS 特有的西里尔编码。本字符集在 4.3.2 版本中得到支持。
cp1251	Windows-1251, win-1251, 1251	Windows 特有的西里尔编码。本字符集在 4.3.2 版本中得到支持。
cp1252	Windows-1252, 1252	Windows 特有的西欧编码。
KOI8-R	koi8-ru, koi8r	俄语。本字符集在 4.3.2 版本中得到支持。
BIG5	950	繁体中文，主要用于中国台湾省。
GB2312	936	简体中文，中国国家标准字符集。
BIG5-HKSCS		繁体中文，附带香港扩展的 Big5 字符集。
Shift_JIS	SJIS, 932	日语
EUC-JP	EUCJP	日语
MacRoman		Mac OS 使用的字符串。
`''`		An empty string activates detection from script encoding (Zend multibyte), default_charset and current locale (see nl_langinfo() and setlocale()), in this order. Not recommended.

注意: 其他字符集没有认可。将会使用默认编码并抛出异常。

返回值

Returns the decoded string.

更新日志

版本	说明
8.1.0	`flags` changed from `ENT_COMPAT` to `ENT_QUOTES` \| `ENT_SUBSTITUTE` \| `ENT_HTML401`.
8.0.0	`encoding` is nullable now.

示例

示例 #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
?>

注释

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

参见

htmlentities() - 将字符转换为 HTML 转义字符
htmlspecialchars() - 将特殊字符转换为 HTML 实体
get_html_translation_table() - 返回使用 htmlspecialchars 和 htmlentities 后的转换表
urldecode() - 解码已编码的 URL 字符串

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用户贡献的备注 5 notes

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130

Martin ¶

13 years ago

If you need something that converts &#[0-9]+ entities to UTF-8, this is simple and works:



<?php

/* Entity crap. /

$input = "Fovi&#269;";



$output = preg_replace_callback("/(&#[0-9]+;)/", function($m) { return mb_convert_encoding($m[1], "UTF-8", "HTML-ENTITIES"); }, $input);



/* Plain UTF-8. */

echo $output;

?>

down

txnull ¶

9 years ago

Use the following to decode all entities:
<?php html_entity_decode($string, ENT_QUOTES | ENT_XML1, 'UTF-8') ?>

I've checked these special entities: 
- double quotes (&#34;)
- single quotes (&#39; and &apos;) 
- non printable chars (e.g. &#13;)
With other $flags some or all won't be decoded.

It seems that ENT_XML1 and ENT_XHTML are identical when decoding.

down

aidan at php dot net ¶

20 years ago

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

down

-1

Benjamin ¶

11 years ago

The following function decodes named and numeric HTML entities and works on UTF-8. Requires iconv.

function decodeHtmlEnt($str) {
    $ret = html_entity_decode($str, ENT_COMPAT, 'UTF-8');
    $p2 = -1;
    for(;;) {
        $p = strpos($ret, '&#', $p2+1);
        if ($p === FALSE)
            break;
        $p2 = strpos($ret, ';', $p);
        if ($p2 === FALSE)
            break;
            
        if (substr($ret, $p+2, 1) == 'x')
            $char = hexdec(substr($ret, $p+3, $p2-$p-3));
        else
            $char = intval(substr($ret, $p+2, $p2-$p-2));
            
        //echo "$char\n";
        $newchar = iconv(
            'UCS-4', 'UTF-8',
            chr(($char>>24)&0xFF).chr(($char>>16)&0xFF).chr(($char>>8)&0xFF).chr($char&0xFF) 
        );
        //echo "$newchar<$p<$p2<<\n";
        $ret = substr_replace($ret, $newchar, $p, 1+$p2-$p);
        $p2 = $p + strlen($newchar);
    }
    return $ret;
}

down

-3

Daniel A. ¶

6 years ago

I wanted to use this function today and I found the documentation, especially about the flags, not particularly helpful.

Running the code below, for example, failed because the flag I used was the wrong one...

$string = 'Donna&#039;s Bakery';
$title = html_entity_decode($string, ENT_HTML401, 'UTF-8');
echo $title;

The correct flag to use in this case is ENT_QUOTES.

My understanding of the flag to use is the one that would correspond to the expected, converted outcome. So, ENT_QUOTES for a character that would be a single or double quote when converted... and so on.

Please help make the documentation a bit clearer.