#include <StringConstants.au3> ; to declare the Constants of StringRegExp
#include <Array.au3> ; UDF needed for _ArrayDisplay and _ArrayConcatenate
Local $sRegex = "(?i)src="([^"]+)""
Local $sString = "<iframe src="https://docs.google.com/presentation/d/1jUSyTkZgZJbFIW6GrACmI67JnR51KKJUCqKUdjs_PuU/embed?start=true&loop=false&delayms=60000" frameborder="0" width="800" height="479" allowfullscreen="true" mozallowfullscreen="true" webkitallowfullscreen="true"></iframe>"
Local $aArray = StringRegExp($sString, $sRegex, $STR_REGEXPARRAYFULLMATCH)
; Present the entire match result
_ArrayDisplay($aArray, "Result")
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