htmlentities

(PHP 4, PHP 5, PHP 7, PHP 8)

htmlentities — 適用可能な文字を全て HTML エンティティに変換する

説明

htmlentities(
    string $string,
    int $flags = ENT_QUOTES | ENT_SUBSTITUTE | ENT_HTML401,
    ?string $encoding = null,
    bool $double_encode = true
): string

この関数はhtmlspecialchars()と同じですが、 HTML エンティティと等価な意味を有する文字をHTMLエンティティに変換します。指定する flags 定数に応じて使われる変換テーブルを得るには、 get_html_translation_table() を使います。

もしデコード (逆の処理) をしたい場合、 html_entity_decode() を使用することができます。

パラメータ

string

入力文字列。

flags

以下のフラグを組み合わせたビットマスクです。クォートや無効な符号単位シーケンス、そして文書型の扱いを指定します。デフォルトは ENT_QUOTES | ENT_SUBSTITUTE | ENT_HTML401 です。

**利用可能な `flags` 定数**
定数名	説明
`ENT_COMPAT`	ダブルクオートは変換しますがシングルクオートは変換しません。
`ENT_QUOTES`	シングルクオートとダブルクオートを共に変換します。
`ENT_NOQUOTES`	シングルクオートとダブルクオートは共に変換されません。
`ENT_IGNORE`	無効な符号単位シーケンスを含む文字列を渡したときに、空の文字列を返すのではなく無効な部分を切り捨てるようになります。このフラグは使わないようにしましょう。 » セキュリティの問題が発生する可能性があります。
`ENT_SUBSTITUTE`	無効な符号単位シーケンスを含む文字列を渡したときに、空の文字列を返すのではなく Unicode の置換文字に置き換えます。 UTF-8 の場合は U+FFFD、それ以外の場合は &#FFFD; となります。
`ENT_DISALLOWED`	指定した文書型において無効な符号位置を、Unicode の代替文字である U+FFFD (UTF-8) あるいは &#FFFD; で置き換えます。これを設定しなければ、無効な符号位置をそのまま残します。これは、外部コンテンツを埋め込んだ XML 文書を整形式に保つために有用です。
`ENT_HTML401`	コードを HTML 4.01 として処理します。
`ENT_XML1`	コードを XML 1 として処理します。
`ENT_XHTML`	コードを XHTML として処理します。
`ENT_HTML5`	コードを HTML 5 として処理します。

encoding

オプションの引数。文字を変換するときに使うエンコーディングを定義します。

省略した場合の encoding のデフォルト値は、 default_charset の値を使います。

技術的にはこの引数を省略可能ですが、 default_charset の指定が入力とは違う文字セットになっている可能性もあるので、適切な値を指定しておくことを強く推奨します。

以下の文字セットをサポートします。

**サポートする文字セット**
文字セット	エイリアス	説明
ISO-8859-1	ISO8859-1	西欧、Latin-1
ISO-8859-5	ISO8859-5	ほとんど使われないキリル文字セット (Latin/Cyrillic)。
ISO-8859-15	ISO8859-15	西欧、Latin-9 。Latin-1(ISO-8859-1) に欠けているユーロ記号やフランス・フィンランドの文字を追加したもの。
UTF-8		ASCII 互換のマルチバイト 8 ビット Unicode 。
cp866	ibm866, 866	DOS 固有のキリル文字セット。
cp1251	Windows-1251, win-1251, 1251	Windows 固有のキリル文字セット。
cp1252	Windows-1252, 1252	西欧のための Windows 固有の文字セット。
KOI8-R	koi8-ru, koi8r	ロシア語。
BIG5	950	繁体字中国語。主に台湾で使用されます。
GB2312	936	簡体字中国語。国の標準文字セットです。
BIG5-HKSCS		Big5 に香港の拡張を含めたもの。繁体字中国語。
Shift_JIS	SJIS, SJIS-win, cp932, 932	日本語。
EUC-JP	EUCJP, eucJP-win	日本語。
MacRoman		Mac OS で使われる文字セット。
`''`		空文字列を指定すると、スクリプトのエンコーディング (Zend multibyte)、 default_charset、そして現在のロケール (nl_langinfo() および setlocale() を参照ください) の順でエンコーディングを検出します。この方法はおすすめしません。

注意: これら以外の文字セットは理解できません。かわりにデフォルトのエンコーディングを使用し、警告を発生させます。

double_encode

double_encode をオフにすると、PHP は既存の html エンティティをエンコードしません。デフォルトでは、既存のエンティティも含めてすべてを変換します。

戻り値

エンコードした文字列を返します。

入力文字列の中に、指定した encoding で無効な符号単位シーケンスが含まれる場合は、 ENT_IGNORE あるいは ENT_SUBSTITUTE フラグが設定されていない限りは空文字列を返します。

変更履歴

バージョン	説明
8.1.0	`flags` のデフォルト値が `ENT_COMPAT` から `ENT_QUOTES` \| `ENT_SUBSTITUTE` \| `ENT_HTML401` に変更されました。
8.0.0	`encoding` は、nullable になりました。

例

例1 htmlentities() の例

<?php
$str = "A 'quote' is <b>bold</b>";

// 出力: A 'quote' is &lt;b&gt;bold&lt;/b&gt;
echo htmlentities($str);

// 出力: A &#039;quote&#039; is &lt;b&gt;bold&lt;/b&gt;
echo htmlentities($str, ENT_QUOTES);
?>

例2 ENT_IGNORE の使用例

<?php
$str = "\x8F!!!";

// 出力: 空の文字列
echo htmlentities($str, ENT_QUOTES, "UTF-8");

// 出力: "!!!"
echo htmlentities($str, ENT_QUOTES | ENT_IGNORE, "UTF-8");
?>

参考

html_entity_decode() - HTML エンティティを対応する文字に変換する
get_html_translation_table() - htmlspecialchars および htmlentities で使用される変換テーブルを返す
htmlspecialchars() - 特殊文字を HTML エンティティに変換する
nl2br() - 改行文字の前に HTML の改行タグを挿入する
urlencode() - 文字列を URL エンコードする

add a note

User Contributed Notes 22 notes

down

154

Sijmen Ruwhof ¶

14 years ago


An important note below about using this function to secure your application against Cross Site Scripting (XSS) vulnerabilities.

When printing user input in an attribute of an HTML tag, the default configuration of htmlEntities() doesn't protect you against XSS, when using single quotes to define the border of the tag's attribute-value. XSS is then possible by injecting a single quote:

<?php
$_GET['a'] = "#000' onload='alert(document.cookie)";
?>

XSS possible (insecure):

<?php
$href = htmlEntities($_GET['a']);
print "<body bgcolor='$href'>"; # results in: <body bgcolor='#000' onload='alert(document.cookie)'>
?>

Use the 'ENT_QUOTES' quote style option, to ensure no XSS is possible and your application is secure:

<?php
$href = htmlEntities($_GET['a'], ENT_QUOTES);
print "<body bgcolor='$href'>"; # results in: <body bgcolor='#000&#039; onload=&#039;alert(document.cookie)'>
?>

The 'ENT_QUOTES' option doesn't protect you against javascript evaluation in certain tag's attributes, like the 'href' attribute of the 'a' tag. When clicked on the link below, the given JavaScript will get executed:

<?php
$_GET['a'] = 'javascript:alert(document.cookie)';
$href = htmlEntities($_GET['a'], ENT_QUOTES);
print "<a href='$href'>link</a>"; # results in: <a href='javascript:alert(document.cookie)'>link</a>
?>

down

j2teamnnl at gmail dot com ¶

2 years ago


The answer above is not correct for multiple languages like France
I had correct it
function xml_entities($strIn)
    {
        if (is_numeric($strIn)) {
            return $strIn;
        }
        $strOut = null;

        $arrStr = mb_str_split($strIn);
        foreach ($arrStr as $char) {
            $ord = mb_ord($char);

            if (($ord > 0 && $ord < 32) || ($ord >= 127)) {
                $strOut .= "&amp;#{$ord};";
            }
            else {
                switch ($char) {
                    case '<':
                        $strOut .= '&lt;';
                        break;
                    case '>':
                        $strOut .= '&gt;';
                        break;
                    case '&':
                        $strOut .= '&amp;';
                        break;
                    case '"':
                        $strOut .= '&quot;';
                        break;
                    default:
                        $strOut .= $char;
                }
            }
        }

        return $strOut;
    }

down

q (dot) rendeiro (at) gmail (dot) com ¶

17 years ago


I've seen lots of functions to convert all the entities, but I needed to do a fulltext search in a db field that had named entities instead of numeric entities (edited by tinymce), so I searched the tinymce source and found a string with the value->entity mapping. So, i wrote the following function to encode the user's query with named entities.

The string I used is different of the original, because i didn't want to convert ' or ". The string is too long, so I had to cut it. To get the original check TinyMCE source and search for nbsp or other entity ;)

<?php

$entities_unmatched = explode(',', '160,nbsp,161,iexcl,162,cent, [...] ');
$even = 1;
foreach($entities_unmatched as $c) {
    if($even) {
        $ord = $c;
    } else {
        $entities_table[$ord] = $c;
    }
    $even = 1 - $even;
}

function encode_named_entities($str) {
    global $entities_table;
    
    $encoded_str = '';
    for($i = 0; $i < strlen($str); $i++) {
        $ent = @$entities_table[ord($str{$i})];
        if($ent) {
            $encoded_str .= "&$ent;";
        } else {
            $encoded_str .= $str{$i};
        }
    }
    return $encoded_str;
}

?>

down

hajo-p ¶

10 years ago


The flag ENT_HTML5 also strips newline chars like \n with htmlentities while htmlspecialchars is not affected by that.

If you want to use nl2br on that string afterwards you might end up searching the problem like i did. This does not apply to other flags like e.g. ENT_XHTML which confused me.

Tested this with PHP 5.4 / 5.5 / 5.6-dev with same results, so it seems that this is an intended "feature".

down

2962051004 at qq dot com ¶

6 years ago


<?php

/**
 * 将中文转为Html实体
 * Convert Chinese in HTML to entity
 * Author QiangGe
 * Mail 2962051004@qq.com
 *
*/

$str = <<<EOT
你好 world
EOT;

function ChineseToEntity($str) {
 return preg_replace_callback(
        '/[\x{4e00}-\x{9fa5}]/u', // utf-8 
        // '/[\x7f-\xff]+/', // if gb2312
        function ($matches) {
            $json = json_encode(array($matches[0]));
            preg_match('/\[\"(.*)\"\]/', $json, $arr);
            /*
             * 通过json_encode函数将中文转为unicode
             * 然后用正则取出unicode
             * Turn the Chinese into Unicode through the json_encode function, then extract Unicode from regular.
             * I think this idea is seamless.
            */
            return '&#x'. str_replace('\\u', '', $arr[1]). ';';
        }, $str
   );
}

echo ChineseToEntity($str);
// &#x4f60;&#x597d; world

down

phil at lavin dot me dot uk ¶

14 years ago


The following will make a string completely safe for XML:

<?php
function philsXMLClean($strin) {
        $strout = null;

        for ($i = 0; $i < strlen($strin); $i++) {
                $ord = ord($strin[$i]);

                if (($ord > 0 && $ord < 32) || ($ord >= 127)) {
                        $strout .= "&amp;#{$ord};";
                }
                else {
                        switch ($strin[$i]) {
                                case '<':
                                        $strout .= '&lt;';
                                        break;
                                case '>':
                                        $strout .= '&gt;';
                                        break;
                                case '&':
                                        $strout .= '&amp;';
                                        break;
                                case '"':
                                        $strout .= '&quot;';
                                        break;
                                default:
                                        $strout .= $strin[$i];
                        }
                }
        }

        return $strout;
}
?>

down

realcj at g mail dt com ¶

18 years ago


If you are building a loadvars page for Flash and have problems with special chars such as " & ", " ' " etc, you should escape them for flash:



Try trace(escape("&")); in flash' actionscript to see the escape code for &;



% = %25

& = %26

' = %27



<?php

function flashentities($string){

return str_replace(array("&","'"),array("%26","%27"),$string);

}

?>



Those are the two that concerned me. YMMV.

down

ustimenko dot alexander at gmail dot com ¶

12 years ago


For those Spanish (and not only) folks, that want their national letters back after htmlentities :)

<?php
protected function _decodeAccented($encodedValue, $options = array()) {
    $options += array(
        'quote'     => ENT_NOQUOTES,
        'encoding'  => 'UTF-8',
    );
    return preg_replace_callback(
        '/&\w(acute|uml|tilde);/',
        create_function(
            '$m',
            'return html_entity_decode($m[0], ' . $options['quote'] . ', "' .
            $options['encoding'] . '");'
        ),
        $encodedValue
    );
}
?>

down

robin at robinwinslow dot co dot uk ¶

13 years ago


htmlentities seems to have changed at some point between version 5.1.6 and 5.3.3, such that it now returns an empty string for anything containing a pound sign:

$ php -v
PHP 5.1.6 (cli) (built: May 22 2008 09:08:44)
$ php -r "echo htmlentities('£hello', null, 'utf-8');"
&pound;hello
$

$ php -v
PHP 5.3.3 (cli) (built: Aug 19 2010 12:07:49)
$ php -r "echo htmlentities('£hello', null, 'utf-8');"
$

(Returns an empty string the second time)

Just a heads up.

down

Bassie (: ¶

21 years ago


Note that you'll have use htmlentities() before any other function who'll edit text like nl2br().

If you use nl2br() first, the htmlentities() function will change < br > to &lt;br&gt;.

down

wd at NOSPAMwd dot it ¶

12 years ago


Hi there,

after several and several tests, I figured out that dot:

- htmlentities() function remove characters like "à","è",etc when you specify a flag and a charset

- htmlentities() function DOES NOT remove characters like those above when you DO NOT specify anything

So, let's assume that..

<?php

$str = "Hèèèllooo";

$res_1 = htmlentities($str, ENT_QUOTES, "UTF-8");
$res_2 = htmlentities($str);

echo var_dump($res_1); // Result: string '' (length=0)
echo var_dump($res_2); // string 'H&egrave;&egrave;&egrave;llooo' (length=30)

?>

I used this for a textarea content for comments. Anyway, note that using the "$res_2" form the function will leave unconverted single/double quotes. At this point you should use str_replace() function to perform the characters but be careful because..

<?php

$str = "'Hèèèllooo'";

$res_2 = str_replace("'","&#039;",$str);
$res_2 = htmlentities($str);
echo var_dump($res_2); // string '&amp;#039;H&egrave;&egrave;&egrave;llooo&amp;#039;'

$res_3 = htmlentities($str);
$res_3 = str_replace("'","&#039;",$res_3);
echo var_dump($res_3); // string '&#039;H&egrave;&egrave;&egrave;llooo&#039;' --> Nice
?>

Hope it will helps you.

Regards,
W.D.

down

Waygood ¶

13 years ago


When putting values inside comment tags <!-- --> you should replace -- with &#45;&#45; too, as this would end your tag and show the rest of the comment.

down

n at erui dot eu ¶

12 years ago


html entities does not encode all unicode characters. It encodes what it can [all of latin1], and the others slip through. &#1033; is the nasty I use. I have searched for a function which encodes everything, but in the end I wrote this. This is as simple as I can get it. Consult an ansii table to custom include/omit chars you want/don't. I'm sure it's not that fast.

// Unicode-proof htmlentities. 
// Returns 'normal' chars as chars and weirdos as numeric html entites.
function superentities( $str ){
    // get rid of existing entities else double-escape
    $str = html_entity_decode(stripslashes($str),ENT_QUOTES,'UTF-8'); 
    $ar = preg_split('/(?<!^)(?!$)/u', $str );  // return array of every multi-byte character
    foreach ($ar as $c){
        $o = ord($c);
        if ( (strlen($c) > 1) || /* multi-byte [unicode] */
            ($o <32 || $o > 126) || /* <- control / latin weirdos -> */
            ($o >33 && $o < 40) ||/* quotes + ambersand */
            ($o >59 && $o < 63) /* html */
        ) {
            // convert to numeric entity
            $c = mb_encode_numericentity($c,array (0x0, 0xffff, 0, 0xffff), 'UTF-8');
        }
        $str2 .= $c;
    }
    return $str2;
}

down

admin at wapforum dot rs ¶

13 years ago


A useful little function to convert the symbols in the different inputs.
<?php
function ConvertSimbols($var, $ConvertQuotes = 0) {
if ($ConvertQuotes > 0) {
$var = htmlentities($var, ENT_NOQUOTES, 'UTF-8');
$var = str_replace('\"', '', $var);
$var = str_replace("\'", '', $var);
} else {
$var = htmlentities($var, ENT_QUOTES, 'UTF-8');
}
return $var;
}
?>

Usage with quotes for example message:

$message = ConvertSimbols($message);

Usage without quotes for example link:

$link = ConvertSimbols($link, 1);

down

Tom Walter ¶

16 years ago


Note that as of 5.2.5 it appears that if the input string contains a character that is not valid for the output encoding you've specified, then this function returns null.

You might expect it to just strip the invalid char, but it doesn't.

You can strip the chars yourself like so:

iconv('utf-8','utf-8',$str);

You can combine that with htmlentities also:

$str = htmlentities(iconv('UTF-8', 'UTF-8//IGNORE', $str, ENT_QUOTES, 'UTF-8');

Should give you a string with htmlentities encoded to utf-8, and any unsupported chars stripped.

down

chris at ocproducts dot com ¶

7 years ago


This function throws a warning on bad input even if ENT_SUBSTITUTE is set, so be prepared for this.

down

jake_mcmahon at hotmail dot com ¶

20 years ago


This fuction is particularly useful against XSS (cross-site-scripting-). XSS makes use of holes in code, whether it be in Javascript or PHP. XSS often, if not always, uses HTML entities to do its evil deeds, so this function in co-operation with your scripts (particularly search or submitting scripts) is a very useful tool in combatting "H4X0rz".

down

steve at mcdragonsoftware dot com ¶

13 years ago


I'm glad 5.4 has xml support, but many of us are working with older installations, some of us still have to use PHP4. If you're like me you've been frustrated with trying to use htmlentites/htmlspecial chars with xml output. I was hoping to find an option to force numeric encoding, lacking that, I have written my own xmlencode function, which I now offer:



usage: 



$string xmlencode( $string )



it will use htmlspecialchars for the valid xml entities amp, quote, lt, gt, (apos) and return the numeric entity for all other non alpha-numeric characters.



-------------------------------------------



<?php 

if( !function_exists( 'xmlentities' ) ) {

    function xmlentities( $string ) {

        $not_in_list = "A-Z0-9a-z\s_-";

        return preg_replace_callback( "/[^{$not_in_list}]/" , 'get_xml_entity_at_index_0' , $string );

    }

    function get_xml_entity_at_index_0( $CHAR ) {

        if( !is_string( $CHAR[0] ) || ( strlen( $CHAR[0] ) > 1 ) ) {

            die( "function: 'get_xml_entity_at_index_0' requires data type: 'char' (single character). '{$CHAR[0]}' does not match this type." );

        }

        switch( $CHAR[0] ) {

            case "'":    case '"':    case '&':    case '<':    case '>':

                return htmlspecialchars( $CHAR[0], ENT_QUOTES );    break;

            default:

                return numeric_entity_4_char($CHAR[0]);                break;

        }        

    }

    function numeric_entity_4_char( $char ) {

        return "&#".str_pad(ord($char), 3, '0', STR_PAD_LEFT).";";

    }    

}

?>

down

Jeff ¶

6 years ago


There is a feature when writing to XML using an AJAX call to PHP that rarely is mentioned. I struggled for many hours using htmlentities() because what was getting written to my XML document was not as expected. I naturally assumed that I should be converting my strings before writing them to XML to adhere to XML rules on illegal characters. To my surprise, when converting with htmlentities() or htmlspecialchars() and then writing to an XML file, the resulting ampersands get converted afterwards! Consider the following example:

<?php
$str = "<b>I am cool</b>" ;
$str = htmlentities($str) ;
?>

When you append $str to an XML element and save() the document, you would expect the XML document's source code to look something like this:

<ele>&lt;b&gt;I am cool&lt;/b&gt;</ele>

But that is not what happens. The resulting ampersands get converted by PHP automatically to &amp; and your source code ends up looking like this:

<ele>&amp;lt;b&amp;gt;I am cool&amp;lt;/b&amp;gt;</ele>

As you can see, this creates problems when trying to output the XML data back to HTML. It is important to remember that when writing to XML this way, special characters like ">" and "<"; PHP converts them automatically and there becomes no need to use htmlentities() in certain cases. I assume this feature is in place to aid with passing data through header queries, to avoid reserved characters conflicting with others in a header query (e.g. & or =). Now I understand this may not be the case with older versions of PHP and that this might be a feature of my version (PHP version 5.6.32). With older versions, I assume using htmlentities() or htmlspecialchars() is a must, as stated with previous notes here. Also I use the charset UTF-8 in my HTML and XML and am not sure if this also effects the results I get.

Anyway, I struggled for many hours with using htmlentities() to convert strings for XML writing and saving, when all I had to do was simply not use the function and let PHP convert my strings for me. I hope this helps because I would think I am not the only one who has struggled with this situation.

down

h_guillaume at hotmail dot com ¶

14 years ago


I use this function to encode all the xml entities and also all the &something; that are not defined in xml like &trade;
You can also decode what you encode with my decode function.
My function works a little like the htmlentities.
You can also add other string to the array if you want to exclude them from the encoding.

<?php
function xml_entity_decode($text, $charset = 'Windows-1252'){
    // Double decode, so if the value was &amp;trade; it will become Trademark
    $text = html_entity_decode($text, ENT_COMPAT, $charset);
    $text = html_entity_decode($text, ENT_COMPAT, $charset);
    return $text;
}

function xml_entities($text, $charset = 'Windows-1252'){
     // Debug and Test
    // $text = "test &amp; &trade; &amp;trade; abc &reg; &amp;reg; &#45;";
    
    // First we encode html characters that are also invalid in xml
    $text = htmlentities($text, ENT_COMPAT, $charset, false);
    
    // XML character entity array from Wiki
    // Note: &apos; is useless in UTF-8 or in UTF-16
    $arr_xml_special_char = array("&quot;","&amp;","&apos;","&lt;","&gt;");
    
    // Building the regex string to exclude all strings with xml special char
    $arr_xml_special_char_regex = "(?";
    foreach($arr_xml_special_char as $key => $value){
        $arr_xml_special_char_regex .= "(?!$value)";
    }
    $arr_xml_special_char_regex .= ")";
    
    // Scan the array for &something_not_xml; syntax
    $pattern = "/$arr_xml_special_char_regex&([a-zA-Z0-9]+;)/";
    
    // Replace the &something_not_xml; with &amp;something_not_xml;
    $replacement = '&amp;${1}';
    return preg_replace($pattern, $replacement, $text);
}
?>

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-1

za at byza dot it ¶

16 years ago


Trouble when using files with different charset?



htmlentities and html_entity_decode can be used to translate between charset! 



Sample function:



<?php

function utf2latin($text) {

   $text=htmlentities($text,ENT_COMPAT,'UTF-8');

   return html_entity_decode($text,ENT_COMPAT,'ISO-8859-1');

}

?>

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-3

drallen at cs dot uwaterloo dot ca ¶

14 years ago


A pointer to http://www.php.net/manual/en/function.mb-convert-encoding.php if your intention is to translate *all* characters in a charset to their corresponding HTML entities, not just named characters. Non-named characters will be replaced with HTML numeric encoding. eg:

$text = mb_convert_encoding($text, 'HTML-ENTITIES', "UTF-8");

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