#include <MsgBoxConstants.au3> ; to declare the Constants of MsgBox
Local $sRegex = "(<p id="nav">)\s?(.*?)\s?(<\/p>)"
Local $sString = "<p id="nav">" & @CRLF & _
"<a href="http://tenupclp.dev/wp-login.php?action=register">Register</a> | <a href="http://tenupclp.dev/wp-login.php?action=lostpassword">Lost your password?</a>" & @CRLF & _
"</p>"
Local $sSubst = "$1fart$3"
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