<iframethe literal text <iframe (case sensitive) *?matches any number of characters from the set below:
\Sany non-whitespace character
\sany whitespace character
src="the literal text src=" (case sensitive) .*?any character (except for line terminators), repeated any number of times
\.the literal . (4610 / 568 / 2E16)
\w+any word character, repeated at least once
\.the literal . (4610 / 568 / 2E16)
.*?any character (except for line terminators), repeated any number of times
"the literal " (3410 / 428 / 2216)
g modifier: global. Finds all matches instead of stopping after the first