Remove HTML Comments with PHP

Discussion

1. MaxArt

   That would strip out all the comment-like sequences in Javascript code.
   A very rare case indeed, and mixing HTML and Javascript is usually deprecated, but still…
   A fully-fledged HTML-Javascript parser just to prevent this is hardly the effort here.

   Just remember that for backward compatibility for older browsers, script tags’ content are often enclosed in a comment. That would remove the entire script.
• MaxArt

  I’d like to add that I usually used the sequence [\s\S] instead of the (capturing) group (.|\s). I think it’s faster.
• Fred

  You can also do (?:.|\s) to make a group non-capturing. [\s\S] (whitespace or no whitespace) is nonsensical, you could just as well do . (any character).

  David: Why do you do .|\s? As far as I know, . captures all characters, including whitespace.
• David Walsh

  I’ll check it out Fred!
2. Jeff Griffiths

   When does this code run?

   The best use I could see for this is a build step, eg you take the template files and them through this on deploy. It feels like a waste of cpu cycles to run something like this per-request?
3. Kristy

   I like this concept but where/when would you call the function for normal php pages? thx
4. I

   This is great.

   For my use, I’d prefer this being done from an htaccess file – is this possible at all?
5. (v)

   what about MSIE conditional comments? ;-)

   my code is like:
   
...
return preg_replace('/<!--(?!\s*(?:\[if [^\]]+]|))(?:(?!-->).)*-->/s', '', $content);
…

• David Walsh

  Awesome point, love this — I’ll check it out and if it works I’ll update my post!
• David Walsh

  I tried this but it didn’t work :/ No comments were stripped at all.
• naden

  Hi David, (V), the following mix of your snippets workes for me

  $data = preg_replace(‘//’, ”, $data);
6. nXqd

   It depends on our framework, it should have a pipeline to minimize the html before sending it into client :D
   But thanks for your useful snippet :)
7. Nick Davidson

   Wouldn’t this alter IE conditional comments?
8. naden

   Hi David, (V), the following mix of your snippets workes for me

   $data = preg_replace(‘//’, ”, $data);

   2nd try, I used pre but the code was removed …
9. naden

   Hi David, (V), the following mix of your snippets workes for me

   http://pastebin.com/bfzWVFUi

   3rd try, I used pre but the code was removed … please delete my two previous comments
10. Mike Smith

    I added this code to my functions.php file, however, visitors can still post strong html tags and images on my blog :(
11. pavan

    good concept and thanks for that
12. spongeBob

    Nice approach. But it would be more believable if I you also removed html comments on this page. :) But I liked the regex.
13. Jack

    Why even bother with putting in HTML comments at all? Since commenting is supposed to be for future developers eyes who will be reading the actual code I just comment in php and then don’t have to worry about comments passed into html.
14. jasa web desain

    Full strip function

    function html2txt($document){
    $search = array('@]*?>.*?@si',  // Strip out javascript
                   '@<[\/\!]*?[^]*?>@si',            // Strip out HTML tags
                   '@]*?>.*?@siU',    // Strip style tags properly
                   '@@'         // Strip multi-line comments including CDATA
    );
    $text = preg_replace($search, '', $document);
    return $text;
    } 
    
15. JoeB

    This crashes horribly if the comment inside the tag is very large.