How can I remove attributes from an html tag?

Question

How can I use php to strip all/any attributes from a tag, say a paragraph tag?

to

Answer 1

Here is one function that will let you strip all attributes except ones you want:

function stripAttributes($s, $allowedattr = array()) {
  if (preg_match_all("/<[^>]*\\s([^>]*)\\/*>/msiU", $s, $res, PREG_SET_ORDER)) {
   foreach ($res as $r) {
     $tag = $r[0];
     $attrs = array();
     preg_match_all("/\\s.*=(['\"]).*\\1/msiU", " " . $r[1], $split, PREG_SET_ORDER);
     foreach ($split as $spl) {
      $attrs[] = $spl[0];
     }
     $newattrs = array();
     foreach ($attrs as $a) {
      $tmp = explode("=", $a);
      if (trim($a) != "" && (!isset($tmp[1]) || (trim($tmp[0]) != "" && !in_array(strtolower(trim($tmp[0])), $allowedattr)))) {

      } else {
          $newattrs[] = $a;
      }
     }
     $attrs = implode(" ", $newattrs);
     $rpl = str_replace($r[1], $attrs, $tag);
     $s = str_replace($tag, $rpl, $s);
   }
  }
  return $s;
}

In example it would be:

echo stripAttributes('
');

or if you eg. want to keep "class" attribute:

echo stripAttributes('
', array('class'));

Or

Assuming you are to send a message to an inbox and you composed your message with CKEDITOR, you can assign the function as follows and echo it to the $message variable before sending. Note the function with the name stripAttributes() will strip off all html tags that are unnecessary. I tried it and it work fine. i only saw the formatting i added like bold e.t.c.

$message = stripAttributes($_POST['message']);

or you can echo $message; for preview.