php匹配网址的正则 几乎可以匹配任何网址

　　^((https?|ftp|news):\/\/)?([a-z]([a-z0-9\-]*[\.。])+([a-z]{2}|aero|arpa|biz|com|coop|edu|gov|info|int|jobs|mil|museum|name|nato|net|org|pro|travel)|(([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.){3}([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5]))(\/[a-z0-9_\-\.~]+)*(\/([a-z0-9_\-\.]*)(\?[a-z0-9+_\-\.%=&]*)?)?(#[a-z][a-z0-9_]*)?$

　　<script type="text/javascript">

　　function IsURL(urlString)

　　{

　　regExp = /^((https?|ftp|news):\/\/)?([a-z]([a-z0-9\-]*[\.。])+([a-z]{2}|aero|arpa|biz|com|coop|edu|gov|info|int|jobs|mil|museum|name|nato|net|org|pro|travel)|(([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.){3}([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5]))(\/[a-z0-9_\-\.~]+)*(\/([a-z0-9_\-\.]*)(\?[a-z0-9+_\-\.%=&]*)?)?(#[a-z][a-z0-9_]*)?$/

　　if (urlString.match(regExp))

　　return "is a url";

　　else

　　return "not a url";

　　}

　　url = "";

　　alert(IsURL(url));

　　</script>