use strict;
my $str = 'aaa<p>Radio and television.<br></p><p>very<br/> popular <BR>in the <BR/>world today.</p><p>Millions of people watch TV. </p><p>That’s because a radio is very small <span_style=":_black;">98.2%</span></p><p>and it‘s easy to carry. <span_style=":_black;">haha100%</span></p>bb';
my $regex = qr/(?i)<(?!br/?>)[^>]*>/mp;
my $subst = '';
my $result = $str =~ s/$regex/$subst/rg;
print "The result of the substitution is' $result\n";
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 Perl, please visit: http://perldoc.perl.org/perlre.html