php 正则表达式提取网页超级链接url的函数

function match_links($document) {
preg_match_all("'</s*a/s.*?href/s*=/s*([/"/'])?(?(1)(.*?)//1|([^/s/>]+))[^>]*>?(.*?)</a>'isx",$document,$links);
while(list($key,$val) = each($links[2])) {
if(!empty($val))
$match['link'][] = $val;
}
while(list($key,$val) = each($links[3])) {
if(!empty($val))
$match['link'][] = $val;
}
while(list($key,$val) = each($links[4])) {
if(!empty($val))
$match['content'][] = $val;
}
while(list($key,$val) = each($links[0])) {
if(!empty($val))
$match['all'][] = $val;
}
return $match;
}

public string GetHref(string HtmlCode)
{
string MatchVale = "";
string Reg = @"(h|H)(r|R)(e|E)(f|F) *= *('|"")?((/w|//|//|/.|:|-|_)+)('|""| *|>)?";
foreach (Match m in Regex.Matches(HtmlCode, Reg))
{
MatchVale += (m.Value).ToLower().Replace("href=", "").Trim() + "||";
}
return MatchVale;
}