php匹配任何网址的正则表达式

<script type="text/javascript">
/**
*匹配任何网址的正则表达式
*www.jb200.com at 20130509
*/
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>