php去除HTML标记

<script type="text/javascript" src="http://pagead2.googlesyndication.com/pagead/show_ads.js"> </script>

<?
function Text2Html($txt){
$txt = str_replace(" ","　",$txt);
$txt = str_replace("<","&lt;",$txt);


$txt = str_replace(">","&gt;",$txt);
$txt = preg_replace("/[rn]{1,}/isU","
rn",$txt);
return $txt; }

?>