use strict;
my $str = '<div class="class1<ins>class2</ins>" style=";display:block;">Some Text</div>
';
my $regex = qr/(?<=[a-zA-Z]=")([\w\W]*)(?:<ins>|<del>)([\w\W\s]*)(?:<\/ins>|<\/del>)([\w\W]*)(?=">)/p;
my $subst = '$1 $2 $3';
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