#!/usr/bin/perl -w
use strict;

my @strings = (
'<a href="#1">HIT<b>MUST MATCH</b></a> <a href="#2">2</a>',
'<a href="#1">HIT<a name="MUST NOT MATCH">-</a> <a href="#2">2</a>'
); 
 
foreach my $string (@strings) {
"" =~ /()/;		# set $1 to false
$string =~ /
(						# the whole match should be catches as $1
	HIT					# start at the first found "HIT"
	(?=					# begin of positive Lookahead
		[^<]*?			# zero or more characters other than "<" 
		(?!				# start a negative Lookahead
			<a[^>]*?>	# an opening a tag is forbidden
		)				
		.*?<\/a>		# any characters until the closing a tag
	)					# end of positive Lookahead
	.*?					# catch all chars after HIT,
	<\/a>				# non-greedy until the first closing a tag
)
/x;

print "\nstring:\t$string\n";
if ($1) { print "match:\t$1\n" }
else { print "NO match!\n" }
}