International PHP Conference 2015

strip_tags

(PHP 4, PHP 5)

strip_tagsStrip HTML and PHP tags from a string

Description

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

This function tries to return a string with all NULL bytes, HTML and PHP tags stripped from a given str. It uses the same tag stripping state machine as the fgetss() function.

Parameters

str

The input string.

allowable_tags

You can use the optional second parameter to specify tags which should not be stripped.

Note:

HTML comments and PHP tags are also stripped. This is hardcoded and can not be changed with allowable_tags.

Note:

In PHP 5.3.4 and later, self-closing XHTML tags are ignored and only non-self-closing tags should be used in str. For example, to allow both <br> and <br/>, you should use:

<?php
strip_tags
($input'<br>');
?>

Return Values

Returns the stripped string.

Changelog

Version Description
5.3.4 strip_tags() ignores self-closing XHTML tags in allowable_tags.
5.0.0 strip_tags() is now binary safe.

Examples

Example #1 strip_tags() example

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

// Allow <p> and <a>
echo strip_tags($text'<p><a>');
?>

The above example will output:

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

Notes

Warning

Because strip_tags() does not actually validate the HTML, partial or broken tags can result in the removal of more text/data than expected.

Warning

This function does not modify any attributes on the tags that you allow using allowable_tags, including the style and onmouseover attributes that a mischievous user may abuse when posting text that will be shown to other users.

Note:

Tag names within the input HTML that are greater than 1023 bytes in length will be treated as though they are invalid, regardless of the allowable_tags parameter.

See Also

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