Clean string from html tags and special characters - preg-replace

Question

I want to clean my text from html tags, html spacial characters and characters like < > [ ] / \ * ,
I used $str = preg_replace("/&#?[a-zA-Z0-9]+;/i", "", $str);
it works well with html special characters but some characters doesn't remove like :
( /*/*]]>*/ )
how can I remove these characters?

Answer 1

If you are really using php as it looks like, you can just use:
$str = htmlspecialchars($str);
All HTML chars will be escaped (which could be better than just stripping them). If you really want just to filter these characters, what you need to do is escape those characters on the chars list:
$str = preg_replace("/[\&#\?\]\[\/\\\<\>\*\:\(\);]*/i","",$str);
Notice there's just one "/[]*/i", I removed the a-zA-Z0-9 as you should want these chars in. You can also classify only the desired chars to enter your string (will give you trouble with accentuations like á é ü if you use them, you have to specify every accepted char):
$str = preg_replace("/[^a-zA-Z0-9áÁéÉíÍãÃüÜõÕñÑ\.\+\-\_\%\$\#\!\=;]*/","",$str);
Notice also there's never too much to escape characters, unless for example for the intervals (\a-\z would do fine, \a-\z would match a, or -, or z).
I hope it helps. :)

Answer 2

Regular expression for html tags is:
/\<(.*)?\>/
so use something like this:
// The regular expression to remove HTML tags
$htmltagsregex = '/\<(.*)?\>/';
// what shit will substitute it
$nothing = '';
// the string I want to apply it to
$string = 'this is a string with <b>HTML tags</b> that I want to <strong>remove</strong>';
// DO IT
$result = preg_replace ($htmltagsregex,nothing,$string);
and it will return
this is a string with HTML tags that I want to remove
That's all