htmlentities

(PHP 4, PHP 5, PHP 7)

htmlentities — 将字符转换为 HTML 转义字符

说明

htmlentities ( string $string [, int $flags = ENT_COMPAT | ENT_HTML401 [, string $encoding = ini_get("default_charset") [, bool $double_encode = true ]]] ) : string

本函数各方面都和 htmlspecialchars() 一样， 除了 htmlentities() 会转换所有具有 HTML 实体的字符。

如果要解码（反向操作），可以使用 html_entity_decode()。

参数

string

输入字符。

flags

以下一组位掩码标记，用于设置如何处理引号、无效代码序列、使用文档的类型。 默认是 ENT_COMPAT | ENT_HTML401。

有效 flags 标记常量
常量名 描述
ENT_COMPAT 会转换双引号，不转换单引号。
ENT_QUOTES 既转换双引号也转换单引号。
ENT_NOQUOTES 单/双引号都不转换
ENT_IGNORE 静默丢弃无效的代码单元序列，而不是返回空字符串。 不建议使用此标记， 因为它» 可能有安全影响。
ENT_SUBSTITUTE 替换无效的代码单元序列为 Unicode 代替符（Replacement Character）， U+FFFD (UTF-8) 或者 � (其他)，而不是返回空字符串。
ENT_DISALLOWED 为文档的无效代码点替换为 Unicode 代替符（Replacement Character）： U+FFFD (UTF-8)，或 �（其他），而不是把它们留在原处。 比如以下情况下就很有用：要保证 XML 文档嵌入额外内容时格式合法。
ENT_HTML401 以 HTML 4.01 处理代码。
ENT_XML1 以 XML 1 处理代码。
ENT_XHTML 以 XHTML 处理代码。
ENT_HTML5 以 HTML 5 处理代码。

encoding

An optional argument defining the encoding used when converting characters.

If omitted, the default value of the encoding varies depending on the PHP version in use. In PHP 5.6 and later, the default_charset configuration option is used as the default value. PHP 5.4 and 5.5 will use UTF-8 as the default. Earlier versions of PHP use ISO-8859-1.

Although this argument is technically optional, you are highly encouraged to specify the correct value for your code if you are using PHP 5.5 or earlier, or if your 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.

Note: 其他字符集没有认可。将会使用默认编码并抛出异常。

double_encode

关闭 double_encode 时，PHP 不会转换现有的 HTML 实体， 默认是全部转换。

返回值

返回编码后的字符。

如果指定的编码 encoding 里， string 包含了无效的代码单元序列， 没有设置 ENT_IGNORE 或者 ENT_SUBSTITUTE 标记的情况下，会返回空字符串。

更新日志

版本 说明
5.6.0 The default value for the encoding parameter was changed to be the value of the default_charset configuration option.
5.4.0 encoding 参数的默认值改成 UTF-8。
5.4.0 增加常量 ENT_SUBSTITUTE、 ENT_DISALLOWED、 ENT_HTML401、 ENT_XML1、 ENT_XHTML、 ENT_HTML5。
5.3.0 增加常量 ENT_IGNORE。
5.2.3 增加参数 double_encode。

范例

Example #1 htmlentities() 例子

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

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

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

Example #2 ENT_IGNORE 用法示例

<?php
$str = "\x8F!!!";

// 输出空 string
echo htmlentities($str, ENT_QUOTES, "UTF-8");

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

参见

User Contributed Notes

2962051004 at qq dot com 03-Oct-2018 04:09
<?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
Jeff 01-Jun-2018 01:25
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.
chris at ocproducts dot com 10-Apr-2017 01:10
This function throws a warning on bad input even if ENT_SUBSTITUTE is set, so be prepared for this.
hajo-p 05-Jan-2014 05:18
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".
ustimenko dot alexander at gmail dot com 09-Apr-2012 02:15
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
    );
}
?>
n at erui dot eu 20-Mar-2012 12:46
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;
}
wd at NOSPAMwd dot it 19-Dec-2011 02:20
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.
steve at mcdragonsoftware dot com 16-Nov-2011 08:59
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).";";
    }   
}
?>
Waygood 06-Jun-2011 02:09
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.
robin at robinwinslow dot co dot uk 15-Apr-2011 08:14
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.
admin at wapforum dot rs 24-Feb-2011 01:11
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);
drallen at cs dot uwaterloo dot ca 29-Sep-2010 04:11
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");
h_guillaume at hotmail dot com 17-Sep-2010 01:14
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);
}
?>
Sijmen Ruwhof 13-Sep-2010 12:18
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>
?>
phil at lavin dot me dot uk 08-Apr-2010 08:34
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;
}
?>
Tom Walter 16-Oct-2008 07:14
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.
za at byza dot it 15-Apr-2008 09:15
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');
}
?>
q (dot) rendeiro (at) gmail (dot) com 07-Mar-2007 04:41
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;
}

?>
realcj at g mail dt com 06-Nov-2006 10:41
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.
jake_mcmahon at hotmail dot com 29-Apr-2004 02:29
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".
Bassie (: 05-Jan-2003 04:07
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;.