(PHP 4, PHP 5, PHP 7, PHP 8)
htmlspecialchars — 特殊文字を HTML エンティティに変換する
$string,$flags = ENT_QUOTES | ENT_SUBSTITUTE | ENT_HTML401,$encoding = null,$double_encode = true文字の中には HTML において特殊な意味を持つものがあり、 それらの本来の値を表示したければ HTML の表現形式に変換してやらなければなりません。 この関数は、これらの変換を行った結果の文字列を返します。 入力文字列の中で名前付きエンティティに関連づけられたものを すべて変換する必要がある場合には、代わりに htmlentities() を使用してください。
この関数への入力文字列と最終的なドキュメントとの間で文字セットが一致している場合は、 この関数を使えば HTML ドキュメントに組み込むための準備として十分です。 しかし、この関数への入力の中に、最終的なドキュメントの文字セットでは符号化できない文字がある場合もあります。 そんな文字も (数値エンティティや名前つきエンティティなどで) 残したい場合は、 この関数と htmlentities() (これは、名前付きエンティティに対応する文字しか置換しません) を使うだけでは不十分です。そんな場合は mb_encode_numericentity() を使う必要があります。
| 変換前 | 変換後 |
|---|---|
& (アンパサンド) |
& |
" (ダブルクォート) |
ENT_NOQUOTES が指定されていない場合、" |
' (シングルクォート) |
' (ENT_HTML401 の場合) あるいは ' (
ENT_XML1、ENT_XHTML、
ENT_HTML5 の場合)。ただし
ENT_QUOTES が指定されている場合に限る
|
< (小なり) |
< |
> (大なり) |
> |
string変換される文字列。
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。
| 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 � 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 � 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。
この関数を使ううえでは
ISO-8859-1 と ISO-8859-15、
UTF-8、cp866、
cp1251、cp1252 そして
KOI8-R は事実上同等です。
string 自体がそのエンコーディングにおける有効な文字列である限り、
これらのエンコーディングでは
htmlspecialchars() の影響が及ぶ文字がみな同じ位置にあるからです。
以下の文字セットをサポートします。
| 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。
変換後の文字列を返します。
入力の string の中に
エンコーディング encoding における無効なコードユニットシーケンスが含まれており、
かつ ENT_IGNORE フラグが設定されていなければ、
htmlspecialchars() は空文字列を返します。
| 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。
|
例1 htmlspecialchars() の例
<?php
$new = htmlspecialchars("<a href='test'>Test</a>", ENT_QUOTES);
echo $new; // <a href='test'>Test</a>
?>注意:
この関数は上記のあげたもの以外に関しては一切の変換を行わないことに注意してください。 すべての変換を行うには htmlentities() を参照ください。
注意:
flagsの値が曖昧な場合、以下のルールが適用されます:
ENT_COMPAT,ENT_QUOTES,ENT_NOQUOTESのいずれも存在しない場合、 デフォルトはENT_NOQUOTESになります。ENT_COMPAT,ENT_QUOTES,ENT_NOQUOTESのうちひとつ以上が存在する場合、ENT_QUOTESがもっとも優先度が高くなり、 その後にENT_COMPATが続きます。ENT_HTML401,ENT_HTML5,ENT_XHTML,ENT_XML1のいずれも存在しなければ、 デフォルトはENT_HTML401になります。ENT_HTML401,ENT_HTML5,ENT_XHTML,ENT_XML1のうちひとつ以上が存在している場合、ENT_HTML5が最も優先度が高くなり、ENT_XHTML,ENT_XML1そしてENT_HTML401の順に続きます。ENT_DISALLOWED,ENT_IGNORE,ENT_SUBSTITUTEのうち、ひとつ以上が存在している場合、ENT_IGNOREの優先度がもっとも高くなり、ENT_SUBSTITUTEがその後に続きます。
As of PHP 5.4 they changed default encoding from "ISO-8859-1" to "UTF-8". So if you get null from htmlspecialchars or htmlentities
where you have only set
<?php
echo htmlspecialchars($string);
echo htmlentities($string);
?>
you can fix it by
<?php
echo htmlspecialchars($string, ENT_COMPAT,'ISO-8859-1', true);
echo htmlentities($string, ENT_COMPAT,'ISO-8859-1', true);
?>
On linux you can find the scripts you need to fix by
grep -Rl "htmlspecialchars\\|htmlentities" /path/to/php/scripts/Unfortunately, as far as I can tell, the PHP devs did not provide ANY way to set the default encoding used by htmlspecialchars() or htmlentities(), even though they changed the default encoding in PHP 5.4 (*golf clap for PHP devs*). To save someone the time of trying it, this does not work:
<?php
ini_set('default_charset', $charset); // doesn't work.
?>
Unfortunately, the only way to not have to explicitly provide the second and third parameter every single time this function is called (which gets extremely tedious) is to write your own function as a wrapper:
<?php
define('CHARSET', 'ISO-8859-1');
define('REPLACE_FLAGS', ENT_COMPAT | ENT_XHTML);
function html($string) {
return htmlspecialchars($string, REPLACE_FLAGS, CHARSET);
}
echo html("ñ"); // works
?>
You can do the same for htmlentities()i searched for a while for a script, that could see the difference between an html tag and just < and > placed in the text,
the reason is that i recieve text from a database,
wich is inserted by an html form, and contains text and html tags,
the text can contain < and >, so does the tags,
with htmlspecialchars you can validate your text to XHTML,
but you'll also change the tags, like <b> to <b>,
so i needed a script that could see the difference between those two...
but i couldn't find one so i made my own one,
i havent fully tested it, but the parts i tested worked perfect!
just for people that were searching for something like this,
it may looks big, could be done easier, but it works for me, so im happy.
<?php
function fixtags($text){
$text = htmlspecialchars($text);
$text = preg_replace("/=/", "=\"\"", $text);
$text = preg_replace("/"/", ""\"", $text);
$tags = "/<(\/|)(\w*)(\ |)(\w*)([\\\=]*)(?|(\")\""\"|)(?|(.*)?"(\")|)([\ ]?)(\/|)>/i";
$replacement = "<$1$2$3$4$5$6$7$8$9$10>";
$text = preg_replace($tags, $replacement, $text);
$text = preg_replace("/=\"\"/", "=", $text);
return $text;
}
?>
an example:
<?php
$string = "
this is smaller < than this<br />
this is greater > than this<br />
this is the same = as this<br />
<a href=\"http://www.example.com/example.php?test=test\">This is a link</a><br />
<b>Bold</b> <i>italic</i> etc...";
echo fixtags($string);
?>
will echo:
this is smaller < than this<br />
this is greater > than this<br />
this is the same = as this<br />
<a href="http://www.example.com/example.php?test=test">This is a link</a><br />
<b>Bold</b> <i>italic</i> etc...
I hope its helpfull!!if your goal is just to protect your page from Cross Site Scripting (XSS) attack, or just to show HTML tags on a web page (showing <body> on the page, for example), then using htmlspecialchars() is good enough and better than using htmlentities(). A minor point is htmlspecialchars() is faster than htmlentities(). A more important point is, when we use htmlspecialchars($s) in our code, it is automatically compatible with UTF-8 string. Otherwise, if we use htmlentities($s), and there happens to be foreign characters in the string $s in UTF-8 encoding, then htmlentities() is going to mess it up, as it modifies the byte 0x80 to 0xFF in the string to entities like é. (unless you specifically provide a second argument and a third argument to htmlentities(), with the third argument being "UTF-8").
The reason htmlspecialchars($s) already works with UTF-8 string is that, it changes bytes that are in the range 0x00 to 0x7F to < etc, while leaving bytes in the range 0x80 to 0xFF unchanged. We may wonder whether htmlspecialchars() may accidentally change any byte in a 2 to 4 byte UTF-8 character to < etc. The answer is, it won't. When a UTF-8 character is 2 to 4 bytes long, all the bytes in this character is in the 0x80 to 0xFF range. None can be in the 0x00 to 0x7F range. When a UTF-8 character is 1 byte long, it is just the same as ASCII, which is 7 bit, from 0x00 to 0x7F. As a result, when a UTF-8 character is 1 byte long, htmlspecialchars($s) will do its job, and when the UTF-8 character is 2 to 4 bytes long, htmlspecialchars($s) will just pass those bytes unchanged. So htmlspecialchars($s) will do the same job no matter whether $s is in ASCII, ISO-8859-1 (Latin-1), or UTF-8.Because the documentation says
int $flags = ENT_QUOTES | ENT_SUBSTITUTE | ENT_HTML401
you would think that ENT_HTML401 is important. But as the notes mention, ENT_HTML401 is the default if you don't specify the doc type. This is because ENT_HTML401 === 0. So
int $flags = ENT_QUOTES | ENT_SUBSTITUTE | ENT_HTML401
is exactly equivalent to
int $flags = ENT_QUOTES | ENT_SUBSTITUTEAnother thing important to mention is that
htmlspecialchars(NULL)
returnes an empty string and not NULL!One MUST specify ENT_HTML5 in addition to double_encode=false to avoid double-encoding.
The reason is that contrary to the documentation, double_encode=false will NOT unconditionally and globally prevent double-encoding of ALL existing entities. Crucially, it will only skip double-encoding for THOSE character entities that are explicitly valid for the document type chosen!
Since ENT_HTML5 references the most expansive list of character entities, it is the only setting that will be most lenient with existing character entities.
<?php
declare(strict_types=1);
$text = 'ampersand(&), double quote("), single quote('), less than(<), greater than(>), numeric entities(&"'<>), HTML 5 entities(+,!$(ņ€)';
$result3 = htmlspecialchars( $text, ENT_NOQUOTES | ENT_SUBSTITUTE, 'UTF-8', /*double_encode*/false );
$result4 = htmlspecialchars( $text, ENT_NOQUOTES | ENT_XML1 | ENT_SUBSTITUTE, 'UTF-8', /*double_encode*/false );
$result5 = htmlspecialchars( $text, ENT_NOQUOTES | ENT_XHTML | ENT_SUBSTITUTE, 'UTF-8', /*double_encode*/false );
$result6 = htmlspecialchars( $text, ENT_NOQUOTES | ENT_HTML5 | ENT_SUBSTITUTE, 'UTF-8', /*double_encode*/false );
echo "<br />\r\nHTML 4.01:<br />\r\n", $result3,
"<br />\r\nXML 1:<br />\r\n", $result4,
"<br />\r\nXHTML:<br />\r\n", $result5,
"<br />\r\nHTML 5:<br />\r\n", $result6, "<br />\r\n";
?>
will produce:
HTML 4.01 (will NOT recognize single quote, but Euro):
ampersand(&), double quote("), single quote('), less than(<), greater than(>), numeric entities(&"'<>), HTML 5 entities(+,!$(ņ€)
XML 1 (WILL recognize single quote, but NOT Euro):
ampersand(&), double quote("), single quote('), less than(<), greater than(>), numeric entities(&"'<>), HTML 5 entities(+,!$(ņ€)
XHTML (recognizes single quote and Euro):
ampersand(&), double quote("), single quote('), less than(<), greater than(>), numeric entities(&"'<>), HTML 5 entities(+,!$(ņ€)
HTML 5 (recognizes "all" valid character entities):
ampersand(&), double quote("), single quote('), less than(<), greater than(>), numeric entities(&"'<>), HTML 5 entities(+,!$(ņ€)Be careful, the "charset" argument IS case sensitive. This is counter-intuitive and serves no practical purpose because the HTML spec actually has the opposite.Thanks Thomasvdbulk for your workaround, I would like to add a precision:
When the HTML contains a link tag without new line before the script doesn't work :/
Your example:
<?php
$string = "
this is smaller < than this<br />
this is greater > than this<br />
this is the same = as this<br />
<a href=\"http://www.example.com/example.php?test=test\">This is a link</a><br />
<b>Bold</b> <i>italic</i> etc...";
echo fixtags($string);
?>
Works but this doesn't work:
<?php
$string = "
this is smaller < than this<br />
this is greater > than this<br />
this is the same = as this<br /><a href=\"http://www.example.com/example.php?test=test\">This is a link</a><br />
<b>Bold</b> <i>italic</i> etc...";
echo fixtags($string);
?>
So I add a little workaround at the beginning (before htmlspecialchars):
<?php
$text = preg_replace('/<a/', "\r\n<a", $text);
?>
I don't like that but I don't find other solution... :/If you use htmlspecialchars() to escape any HTML attribute, make sure use double quote instead of single quote for the attribute.
For Example,
> Wrap with Single Quote
<?php
echo "<p title='" . htmlspecialchars("Hello\"s\'world") . "'">
// title will end up Hello"s\ and rest of the text after single quote will be cut off.
?>
> Wrap with Double quote :
<?php
echo '<p title="' . htmlspecialchars("Hello\"s\'world") . '"'>
// title will show up correctly as Hello"s'world
?>Just a few notes on how one can use htmlspecialchars() and htmlentities() to filter user input on forms for later display and/or database storage...
1. Use htmlspecialchars() to filter text input values for html input tags. i.e.,
echo '<input name=userdata type=text value="'.htmlspecialchars($data).'" />';
2. Use htmlentities() to filter the same data values for most other kinds of html tags, i.e.,
echo '<p>'.htmlentities($data).'</p>';
3. Use your database escape string function to filter the data for database updates & insertions, for instance, using postgresql,
pg_query($connection,"UPDATE datatable SET datavalue='".pg_escape_string($data)."'");
This strategy seems to work well and consistently, without restricting anything the user might like to type and display, while still providing a good deal of protection against a wide variety of html and database escape sequence injections, which might otherwise be introduced through deliberate and/or accidental input of such character sequences by users submitting their input data via html forms.This may seem obvious, but it caused me some frustration. If you try and use htmlspecialchars with the $charset argument set and the string you run it on is not actually the same charset you specify, you get any empty string returned without any notice/warning/error.
<?php
$ok_utf8 = "A valid UTF-8 string";
$bad_utf8 = "An invalid UTF-8 string";
var_dump(htmlspecialchars($bad_utf8, ENT_NOQUOTES, 'UTF-8')); // string(0) ""
var_dump(htmlspecialchars($ok_utf8, ENT_NOQUOTES, 'UTF-8')); // string(20) "A valid UTF-8 string"
?>
So make sure your charsets are consistent
<?php
$bad_utf8 = "An invalid UTF-8 string";
// make sure it's really UTF-8
$bad_utf8 = mb_convert_encoding($bad_utf8, 'UTF-8', mb_detect_encoding($bad_utf8));
var_dump(htmlspecialchars($bad_utf8, ENT_NOQUOTES, 'UTF-8')); // string(23) "An invalid UTF-8 string"
?>
I had this problem because a Mac user was submitting posts copy/pasted from a program and it contained weird chars in it.I was recently exploring some code when I saw this being used to make data safe for "SQL".
This function should not be used to make data SQL safe (although to prevent phishing it is perfectly good).
Here is an example of how NOT to use this function:
<?php
$username = htmlspecialchars(trim("$_POST[username]"));
$uniqueuser = $realm_db->query("SELECT `login` FROM `accounts` WHERE `login` = '$username'");
?>
(Only other check on $_POST['username'] is to make sure it isn't empty which it is after trim on a white space only name)
The problem here is that it is left to default which allows single quote marks which are used in the sql query. Turning on magic quotes might fix it but you should not rely on magic quotes, in fact you should never use it and fix the code instead. There are also problems with \ not being escaped. Even if magic quotes were used there would be the problem of allowing usernames longer than the limit and having some really weird usernames given they are to be used outside of html, this just provide a front end for registering to another system using mysql. Of course using it on the output wouldn;t cause that problem.
Another way to make something of a fix would be to use ENT_QUOTE or do:
<?php
$uniqueuser = $realm_db->query('SELECT `login` FROM `accounts` WHERE `login` = "'.$username.'";');
?>
Eitherway none of these solutions are good practice and are not entirely unflawed. This function should simply never be used in such a fashion.
I hope this will prevent newbies using this function incorrectly (as they apparently do).Actually, if you're using >= 4.0.5, this should theoretically be quicker (less overhead anyway):
$text = str_replace(array(">", "<", """, "&"), array(">", "<", "\"", "&"), $text);Be aware of the encoding of your source files!!!
Some of the suggestions here make reference to workarounds where you hard-code an encoding.
<?php
echo htmlspecialchars('<b>Wörmann</b>'); // Why isn't this working?
?>
As it turns out, it may actually be your text editor that is to blame.
As of PHP 5.4, htmlspecialchars now defaults to the UTF-8 encoding. That said, many text editors default to non-UTF encodings like ISO-8859-1 (i.e. Latin-1) or WIN-1252. If you change the encoding of the file to UTF-8, the code above will now work (i.e. the ö is encoded differently in UTF-8 and ISO-8859-1, and you need the UTF-8 version).
Make sure you are editing in UTF-8 Unicode mode! Check your UI or manual for how to convert files to Unicode. It's also a good idea to figure out where to look in your UI to see what the current file encoding is.Problem
In many PHP legacy products the function htmlspecialchars($string) is used to convert characters like < and > and quotes a.s.o to HTML-entities. That avoids the interpretation of HTML Tags and asymmetric quote situations.
Since PHP 5.4 for $string in htmlspecialchars($string) utf8 characters are expected if no charset is defined explicitly as third parameter in the function. Legacy products are mostly in Latin1 (alias iso-8859-1) what makes the functions htmlspecialchars(), htmlentites() and html_entity_decode() to return empty strings if a special character, e. g. a German Umlaut, is present in $string:
PHP<5.4
echo htmlspecialchars('<b>Woermann</b>') //Output: <b>Woermann<b>
echo htmlspecialchars('Wörmann') //Output: <b>Wörmann<b>
PHP=5.4
echo htmlspecialchars('<b>Woermann</b>') //Output: <b>Woermann<b>
echo htmlspecialchars('<b>Wörmann</b>') //Output: empty
Three alternative solutions
a) Not runnig legacy products on PHP 5.4
b) Change all find spots in your code from
htmlspecialchars($string) and *** to
htmlspecialchars($string, ENT_COMPAT | ENT_HTML401, 'ISO-8859-1')
c) Replace all htmlspecialchars() and *** with a new self-made function
*** The same is true for htmlentities() and html_entity_decode();
Solution c
1 Make Search and Replace in the concerned legacy project:
Search for: htmlspecialchars
Replace with: htmlXspecialchars
Search for: htmlentities
Replace with: htmlXentities
Search for: html_entity_decode
Replace with: htmlX_entity_decode
2a Copy and paste the following three functions into an existing already everywhere included PHP-file in your legacy project. (of course that PHP-file must be included only once per request, otherwise you will get a Redeclare Function Fatal Error).
function htmlXspecialchars($string, $ent=ENT_COMPAT, $charset='ISO-8859-1') {
return htmlspecialchars($string, $ent, $charset);
}
function htmlXentities($string, $ent=ENT_COMPAT, $charset='ISO-8859-1') {
return htmlentities($string, $ent, $charset);
}
function htmlX_entity_decode($string, $ent=ENT_COMPAT, $charset='ISO-8859-1') {
return html_entity_decode($string, $ent, $charset);
}
or 2b crate a new PHP-file containing the three functions mentioned above, let's say, z. B. htmlXfunctions.inc.php and include it on the first line of every PHP-file in your legacy product like this: require_once('htmlXfunctions.inc.php').I had problems with spanish special characters. So i think in using htmlspecialchars but my strings also contain HTML.
So I used this :) Hope it help
<?php
function htmlspanishchars($str)
{
return str_replace(array("<", ">"), array("<", ">"), htmlspecialchars($str, ENT_NOQUOTES, "UTF-8"));
}
?>also see function "urlencode()", useful for passing text with ampersand and other special chars through url
(i.e. the text is encoded as if sent from form using GET method)
e.g.
<?php
echo "<a href='foo.php?text=".urlencode("foo?&bar!")."'>link</a>";
?>
produces
<a href='foo.php?text=foo%3F%26bar%21'>link</a>
and if the link is followed, the $_GET["text"] in foo.php will contain "foo?&bar!"People, don't use ereg_replace for the most simple string replacing operations (replacing constant string with another).
Use str_replace.