一个正则表达式的问题。有点不理解了
<?php
$a='<span class="ico-block"><a href="#"><img src="http://www.oxford-royale.co.uk/2013/wp-content/themes/ora/images/ico19.png" /></a></span><h2>';
$a=preg_replace("/<[^>]+?>/","\\0\\2\\4\\5",$a);
var_dump($a);
?>
$a='<span class="ico-block"><a href="#"><img src="http://www.oxford-royale.co.uk/2013/wp-content/themes/ora/images/ico19.png" /></a></span><h2>';
$str=preg_replace("/<\/?a([^>]*)>/", "", $a);
var_dump($str);
