url에서 host추출하는 정규식, 만들려면 만들겠지만 이런것 왠지 귀찮다.
출처 : http://stackoverflow.com/questions/27745/getting-parts-of-a-url-regex
// A single regex to parse and breakup a full URL including query parameters and anchors e.g.
// https://www.google.com/dir/1/2/search.html?arg=0-a&arg1=1-b&arg3-c#hash
^((http[s]?|ftp):\/)?\/?([^:\/\s]+)((\/\w+)*\/)([\w\-\.]+[^#?\s]+)(.*)?(#[\w\-]+)?$
// RexEx positions:
url: RegExp['$&'],
protocol:RegExp.$2,
host:RegExp.$3,
path:RegExp.$4,
file:RegExp.$6,
query:RegExp.$7,
hash:RegExp.$8