(?s)applies the following effective flags to the remainder of the pattern: gms s modifier: single line. Allows a dot to match line terminators
class="clearfixthe literal text class="clearfix (case sensitive) .*?any Unicode character, repeated any number of times
a href="the literal text a href=" (case sensitive) Negated Character Class[^"]+ +matches at least one character outside the set below:
"the literal " (3410 / 428 / 2216)
.*?any Unicode character, repeated any number of times
img the literal text img (case sensitive) .*?any Unicode character, repeated any number of times
src="the literal text src=" (case sensitive) Negated Character Class[^"]+ +matches at least one character outside the set below:
"the literal " (3410 / 428 / 2216)
.*?any Unicode character, repeated any number of times
alt="the literal text alt=" (case sensitive) Negated Character Class[^"]+ +matches at least one character outside the set below:
"the literal " (3410 / 428 / 2216)
g modifier: global. Finds all matches instead of stopping after the first
m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string