match.js

var uri = "http://domain.com:80/articles/something";
var regexp = /http:\/\/([^\/]+):[0-9]+\/articles\/[^\/]+/;

var matches = regexp.exec(uri);
console.log(matches);

//[ 'http://domain.com:80/articles/something',
//  'domain.com',
//  index: 0,
//  input: 'http://domain.com:80/articles/something' ]