// vs. RegExp

regexp.js

var host = 'test.om';

/^.+\.[^\.]+\.om$/.exec(host); // returns 'null'

/*
 * The move:
 * 1) new RegExp(/^.+\.[^\.]+\.om$/).exec(host);
 * 2) (new RegExp(/^.+\.[^\.]+\.om$/)).exec(host);
 * 3) (new RegExp('^.+\.[^\.]+\.om$')).exec(host);
 */

(new RegExp('^.+\.[^\.]+\.om$')).exec(host); // returns 'test.om'

//Solution: escaping dot escaper. Thanks @piouPiouM!
(new RegExp('^.+\\.[^\\.]+\\.om$')).exec(host); // returns 'null'