php下过滤HTML代码的函数

/*---------------------- 过滤HTML代码的函数 -----------------------*/ function htmlEncode($string) {   $string=trim($string);   $string=str_replace("&","&",$string);   $string=str_replace("'","'",$string);   $string=str_replace("&amp;","&",$string);   $string=str_replace("&quot;",""",$string);   $string=str_replace("/"",""",$string);   $string=str_replace("&lt;","<",$string);   $string=str_replace("<","<",$string);   $string=str_replace("&gt;",">",$string);   $string=str_replace(">",">",$string);   $string=str_replace("&nbsp;"," ",$string);   $string=nl2br($string);   return $string; }