#include <MsgBoxConstants.au3> ; to declare the Constants of MsgBox
Local $sRegex = "(?mi).*\.(\w{3,})$"
Local $sString = "http://www.w3schools.com/jsref/jsref_regexp_exec.asp" & @CRLF & _
"https://translate.google.com/#en/pt/Thank%20you%20Engr!%20That%20is%20awesome.php" & @CRLF & _
"www.facebook.com/index.asp"
Local $sSubst = "$1"
Local $sResult = StringRegExpReplace($sString, $sRegex, $sSubst)
MsgBox($MB_SYSTEMMODAL, "Result", $sResult)
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for AutoIt, please visit: https://www.autoitscript.com/autoit3/docs/functions/StringRegExp.htm