global

Read-only. true if the g modifier was set when creating the regexp object.

ignoreCase

Read-only. true if the i modifier was set when creating the regexp object.

multiline

Read-only. true if the m modifier was set when creating the regexp object

lastIndex

Contains the position in the string where the next match should start. test() and exec() set this position after a successful match. Only relevant when the g (global) modifier was used.

> var re = /[dn]o+dle/g;
> re.lastIndex;
0
> re.exec("noodle doodle");
["noodle"]
> re.lastIndex;
6
> re.exec("noodle doodle");
["doodle"]
> re.lastIndex;
13
> re.exec("noodle doodle");
null
> re.lastIndex;
0

source

Read-only. Returns the regular expression pattern (without the modifiers).

> var re = /[nd]o+dle/gmi;
> re.source;
"[nd]o+dle"

exec(string)

Matches the input string with the regular expression. A successful match returns an array containing the match and any capturing groups. With the g modifier, it matches the first occurrence and sets the lastIndex property. Returns null when there's no match.

> var re = /([dn])(o+)dle/g;
> re.exec("noodle doodle");
["noodle", "n", "oo"]
> re.exec("noodle doodle");
["doodle", "d", "oo"]

The arrays returned by exec() have two additional properties: index (of the match) and input (the input string being searched).

test(string)

Same as exec() but only returns true or false.

> /noo/.test('Noodle'),
false
> /noo/i.test('Noodle'),
true