处理用户输入HTML

Question

I have a simple textarea where users can input a description for their product on my dummy system. I'm only allowing <b> <u> and <i> tags, without any attributes using the following code:

$description = strip_tags($_POST['description'], "<b><u><i>");
$description = preg_replace("/<([a-z][a-z0-9]*)[^>]*?(\/?)>/i",'<$1$2>', $description);

My problem is when a tag is left without it's closing part, for example:

<b>This is a <i>Test

The <b> and <i> tags will apply to everything that comes after this part. Is there any reliable way to automatically close the tags?

What I want is for the tag to be closed on the end of the user input, but only if it was left open.

Answer 1

I ended up solving the problem by using Tidy. Here's the code:

$tidy = new Tidy();
$description = $tidy->repairString($description, array(
    'output-xml' => true,
    'input-xml' => true,
    'vertical-space' => false
));