Question

Using PHP, how can I remove all tags except anchors (<a>) from an HTML string, and then convert all the reserved characters into their HTML entities except for the <a> tags?

For example, I would to convert this:

<p><a href="http://www.example.com/">Example.com</a> says that 5 < 6.</p>

into this:

<a href="http://www.example.com/">Example.com</a> says that 5 &lt; 6.

Answer 1

I went with HTML Purifier. Click here for the demo which converts the original example properly.

The code for doing this is:

$config = HTMLPurifier_Config::createDefault();
$config->set('Core.Encoding', 'UTF-8');
$config->set('HTML.Allowed', 'a[href]');
$filter = new HTMLPurifier($config);
$output = $filter->purify($input);