it print:

Gene Name
Gene Name
Transcript
Gene
Description
Alignment View
Hit infomation
mmu-miR-705
mmu-miR-705
hsa-let-7d
hsa-let-7e
hsa-miR-483-5p
mmu-miR-683
hsa-miR-650
hsa-miR-920
mmu-miR-709
hsa-miR-26b*
hsa-miR-185
hsa-let-7a
hsa-miR-765
hsa-miR-629*
hsa-miR-19b-2*
hsa-miR-31
mmu-miR-707
hsa-miR-665
hsa-miR-339-5p
hsa-let-7c
hsa-let-7b
hsa-miR-7
hsa-miR-26b*
hsa-let-7g
hsa-miR-382
hsa-miR-454*
hsa-miR-501-5p
mmu-miR-666-5p
hsa-miR-486-3p
hsa-let-7f
mmu-miR-680
hsa-miR-219-2-3p
hsa-miR-153
hsa-miR-26a-2*
hsa-miR-328
hsa-miR-220c
hsa-miR-19a*
hsa-miR-433
hsa-miR-769-5p
hsa-miR-26b*
hsa-miR-19a*
hsa-miR-19b-1*
hsa-miR-25*
hsa-miR-483-5p
mmu-miR-685
hsa-miR-938
mmu-miR-465a-3p
hsa-miR-139-3p
hsa-miR-187*
mmu-miR-687
Features
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It's very wonderful !!!!!!!but If I wanna refine......if I want only print the string with miR or let...so not features, gene etc...I tried to use regular expression:

 #!/usr/local/bin/perl

use warnings;
use strict;
use LWP::Simple;
use HTML::TreeBuilder;
my @files = (["http://microrna.sanger.ac.uk/cgi-bin/targets/v5/detail_
+view.pl?transcript_id=ENST00000226253", "a.txt"],);  
for my $duplet (@files) {
    mirror($duplet->[0], $duplet->[1]);
};
open DATA, 'a.txt';
my $html = do{local $/;<DATA>};
my $p = HTML::TreeBuilder->new;
$p->parse_content($html); # parse_content if you have a string

my @tds = $p->look_down(_tag => q{td}); # get a list of all the td tag
+s
for my $td (@tds){
  my $bold = $td->look_down(_tag => q{b}); # look for a bold tag
  if ($bold=~ m/miR/ || $bold=~ m/let/){
    print $bold->as_text, qq{\n}; # if there is one print the text
  }
}
$p->delete; # when you've finished with it
[download]

but it gives me the error mess "Use of uninitialized value in pattern match (m//) at test.pl line 19, <DATA> line 1.