my $html="<table>\nt1\n<\/table>\n<table>\nt2\n<\/table>\n"

$html =~ m/<table>(.*?)</table>/;   
# Failed, since 'The period '.' matches any character but ``\n''

$html =~ m/<table>(.*?)</table>/s;   
# SUCCESS, since 's modifier (//s): Treat string as a single long 
# line. '.' matches any character, even "\n"'

$html =~ m/<table>[a-zA-Z0-9 \r\n<>"!-=]*?</table>
# SUCCESS - Emulating '.' with defining a own character class, 
# containing 'any' characters (or a subset in this example) including 
# '\n'
# NO s modifier (//s) needed

$html =~ m/<table>[.\n]*?</table>;
# Same as above, but using '.' instead of explicitly listing all 
# characters ...
# Failed, WHY? Why is '.' not allowed within a character class?