Stripping certain xml/html tag from a string.

strip_single_tag.php

<?php
/* 
//Usage:

$txt= '<h2>
  <a 
  href="/w/index.php?title=Lorem_ipsum&amp;action=edit&amp;section=2" 
  title="Edit section: Discovery">edit< / a> <!-- This "a" will be stripped -->
  <a href="/w/index.php?title=Lorem_ipsum&amp;action=edit&amp;section=2" title="Edit section: Discovery">edit< /a> <!-- This "a" will be stripped -->
  <a href="/w/index.php?title=Lorem_ipsum&amp;action=edit&amp;section=2" title="Edit section: Discovery">edit</ a> <!-- This "a" will be stripped -->
  <b>This will "a" be stripped</b>
  <br><br><!-- These "br" will not be stripped-->
  <span class="mw-editsection-bracket">]
  </span></span>
  </h2>';

$txt = strip_single_tag($txt, 'a');
$txt =  strip_single_tag($txt, 'b');
echo $txt;

*/

function strip_single_tag($string, $tag){
	
	$string = preg_replace('/<'.$tag.'(\s*|\s(.|\s)[^>]*)>/i', "", $string);
	$string = preg_replace('/<\s*\/\s*'.$tag.'(\s*|\s(.|\s)[^>]*)>/i', "", $string);	
	return $string;
}