Is there a PHP function to htmlspecialchars() everything except for certain tags?

Question

It would be nice if I could call my_escape($text, '<p><b><i>') that escapes everything except all <p>, <b> and <i> tags. I'm looking for a generic solution where I can specify an arbitrary set of tags. Does this exist? If not what's the best approach to implement it?

Answer 1

in htmlspecialchars function it converts html tags to

& to &
" to "
' to '
< to &lt;
> to &gt;

after convert you can do reverse to decode

<?php
$test="<p><b><a>Test</b></a></p>";

$test = htmlspecialchars($test);

$test = str_replace("&lt;p&gt;", "<p>", $test);
$test = str_replace("&lt;i&gt;", "<i>", $test);
$test = str_replace("&lt;b&gt;", "<b>", $test);
$test = str_replace("&lt;/b&gt;", "</b>", $test);
$test = str_replace("&lt;/i&gt;", "</i>", $test);
$test = str_replace("&lt;/p&gt;", "</p>", $test);

echo $test;
?>

Answer 2

Your best bet is to do something like this

// Add placeholders
$search = array('<p>', '<b>');
$replace = array("\ap\a", "\ab\a");
$text = str_replace($search, $replace, $text);

$text = htmlspecialchars($text);

// Put it all back together
$text = str_replace($replace, $search, $text);

It would be best to use a regular expression, but that is a lot more explaining.