#include <MsgBoxConstants.au3> ; to declare the Constants of MsgBox
Local $sRegex = "(<span class='customer)(' id='phone\$1[^>]*>)([^<]+)"
Local $sString = "GIVEN:" & @CRLF & _
"<div>" & @CRLF & _
" <span class='customer' id='phone$0'>Home</span>" & @CRLF & _
"<br/>" & @CRLF & _
" <span class='customer' id='phone$1'>Business</span>" & @CRLF & _
"<br/>" & @CRLF & _
" <span class='customer' id='phone$2'>Mobile</span>" & @CRLF & _
"</div>" & @CRLF & _
"" & @CRLF & _
"DESIRED:" & @CRLF & _
"<span class='customer NewClass' id='phone$1'>Organization</span>" & @CRLF & _
""
Local $sSubst = "$1 NewClass$2Organization"
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