JavaScript regular expressions can be written as literals: var x = /foo/i. They can also be constructed with the RegExp() object constructor: var y = new RegExp(/foo/i).

RegExp object methods include test(): /foo/i.test('FOO') will return true. String object methods can also accept regexps: 'foo'.search('o') will return 1, the index of the first matching, while 'foo'.match('o') will return an array of matches.

Sources

Flanagan, David. Javascript: The Definitive Guide. 6th ed, O’Reilly, 2011.