#include <MsgBoxConstants.au3> ; to declare the Constants of MsgBox
Local $sRegex = "<span class='indent'>.*?(<br>).*?<\/span>"
Local $sString = "<span class='together'>line one,<br><span class='indent'>line two.</span><br>Line three,<br><span class='indent'>line four,<br>line five,<br>line six,<br>line seven;<br>line eight.<br>Line nine;<br>line ten,<br>line eleven,<br>line twelve.</span><br>Line thriteen,<br><span class='indent'>line fourteen,<br>line fifteen,<br>line sixteen,<br>line seventeen,<br>line eighteen.</span></span>"
Local $sSubst = ""
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