/*
from: http://serverName.net:7777/foo/api/action/region
to: /foo/api/action/region
*/
//1
[''].concat(decodeURI('http://serverName.net:7777/foo/api/action/region').split('/').slice(4)).join('/');
//2 można użyć (.+:[0-9]+) - prosty regex gdy zawsze będzie numer portu
'http://serverName.net/foo/api/action/region'.replace(/^https*:\/\/[\w\.\:\d]+/, '');