PHP: How to strip HTML tag while allowing < and >

Question

Question: How do I strip HTML tags but allow the greater and less-than sign using PHP?

If I used PHP's strip_tags() function, it doesn't quite work:

$string = '<p>if A > B</p>'
echo strip_tags($string);  // if A B
// but I want to output "if A > B"

UPDATE

Basically, I only want to allow/display plain text.

Answer 1

This will strip everything that looks like an HTML tag.

htmlentities(preg_replace('/<\\S.*?>/', '', $text));

Answer 2

Unfortunately the simplest and most reliable way to get this working is to use an HTML parser. This one will do the trick. I don't know if it'll handle HTML fragments like the above. If not, then wrapping to make it acceptable HTML should be trivial.

As others are pointing out, parsing HTML with a regexp has numerous edge cases to cater for, and difficulty, since HTML is not regular.

Answer 3

You can use HTML Purifier this will not only work with the <p>if A > B</p> example which you wrote, but also the example <p>1<2 && 6>4</p> written by DrJokepu.

Given the input <p>1<2 && 6>4</p> with the allowed elements set to none, HTML purifier gives the output: 1<2 && 6>4.

Answer 4

Try this regular expression that I wrote: <([^>]?="(\"|[^"])?")?([^>]?=''(\''|[^''])?'')?[^>]*?>