<?php
function doCode($str) {
	if (!is_array($str)) {
		$str = htmlspecialchars($str);
	} else {
		array_walk_recursive($str, "doArrCode");
	} 
	return $str;
} 
function doArrCode(&$value) {
	$value = doCode($value);
} 

function getUrl($str) {
	$regex = ' /<a\s.*?href\s*?=\s*([\"\']?)([^\s\>\'\"]+)\1.*?>.*?<\/a>/i';
  preg_match_all($regex,$str,$data,PREG_PATTERN_ORDER);
 return $data[2];
}


//以下为测试内容
$str="<a href= http://www.huoyue.org  target=_blank >一</a><a href=http://www.huoyue.org  target=_blank>二</a><a href=http://www.huoyue.org>三</a><a href=http://www.huoyue.org  target=_blank >四</a><a href=\'http://www.huoyue.org\'  target=_blank>五</a><a href=\"http://www.huoyue.org\" target=_blank>六</a><a href  =\"http://www.huoyue.org\" target=_blank >七</a>";
echo "$str<br/><br/>".doCode($str)."<br/><br/>";
var_dump(doCode(getUrl($str)));
?>