几乎可以匹配任何网址

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_]*)?$

实例：

<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 = "http://www.hlwenhan";
alert(IsURL(url));
</script>