正则得到网站主域名

 1 function getDomain() {
 2     var hostname = window.location.hostname;
 3     var ip = hostname.match(/\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}/g);
 4     if (ip) {
 5         return ip;
 6     }
 7     var domain = hostname.match(/([a-z0-9][a-z0-9\-]*?\.(?:com|cn|net|org|gov|info|la|cc|co|jp)(?:\.(?:cn|jp))?)$/);
 8     if (domain) {
 9         return domain[0];
10     }
11     return hostname;
12 }