RegExp object
Properties
length - integer, number of matches after last exec or match methods calls.
input - string, last inspected string.
source - string, source code of the regular expression - string this RegExp was build from.
index - integer, character position where the first successful match begins in a searched string, read-only.
lastIndex - integer, character position where the next match begins in a searched string.
[index] - string | undefined, read-only, returns n-th matched fragment. Index is a zero based index, integer.
Methods
RegExp

(regular-expresion [,flags])

Used for intitalization of new instance of RegExp object. regular-expresion is a string - source of the regular expression.  flags is an optional string and if provided may contain characters 'i' for case insensitive search and/or 'g' - for global search - to find all occurences of source in the input string.
Use this constructor as: var re = new RegExp(...);

test

(input) →  true | false

Checks input string to see if a pattern exists within a string and returns true if so, and false otherwise.

exec

(input)null | RegExp object

Returns this RegExp object with length and list of matches set if pattern exists in input string or null otherwise.