PROPERTY:  RegExp::lastParen

This property contains the last matched parenthesized substring (if any), and as a static property is always refered to using RegExp.lastParen. For example, the following code uses a regular expression containing three parenthesized substrings to search for a match in the string "the fisherman's tale". After successfully matching the substring 'sherm', the lastParen property will hold the value 'r', which is the match made by the last parenthesized substring (any consonant).

Code:
rexp = /([^aeiou\s]){2}([aeiou])+([^aeiou\s]){2}/
rexp("the fisherman's tale")

Output:
r