Given the form

<FORM action="http://www.example.com/survey.cgi" method="POST">
   <SELECT multiple name="select1">
      <OPTION selected value="Component_1_1">Component_1</OPTION>
      <OPTION selected value="Component_1_2">Component_2</OPTION>
      <OPTION          value="Component_1_3">Component_3</OPTION>
      <OPTION          value="Component_1_4">Component_4</OPTION>
   </SELECT>

   <SELECT multiple name="select2">
      <OPTION          value="Component_2_1">Component_1</OPTION>
      <OPTION          value="Component_2_2">Component_2</OPTION>
      <OPTION selected value="Component_2_3">Component_3</OPTION>
      <OPTION          value="Component_2_4">Component_4</OPTION>
   </SELECT>

   <INPUT type="submit" value="Send"><INPUT type="reset">
</FORM>
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the following would create a request using the initial values,

POST 'http://www.example.com/survey.cgi',
     [ select1 => 'Component_1_1',
       select1 => 'Component_1_2',
       select2 => 'Component_2_3',
     ];
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It's easy to see what you should provide by changing the POST to GET and submitting the form to a non existant URL using your web browser: (spacing added for readability)

http://www.example.com/nonexistant.cgi
   ? select1=Component_1_1
   & select1=Component_1_2
   & select2=Component_2_3
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Update: It might be easier for you to build the request as follows:

POST 'http://www.example.com/survey.cgi',
     [ ( map {; select1 => $_ } @select1_values ),
       ( map {; select2 => $_ } @select2_values ),
     ];
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thanks for your reply ,but the unquoted select1 select2 will generate syntax error . The Source code of the form webpage I want to query is written in php as follows

...
<form name="geneCompareTwo" method="post" action="geneCompareTwo2.php"
+>
...
<select name="ontologies[]" multiple="yes"    size="4">
<option selected value="All">All</option>
<option value="biological_process">Biological Process</option>
<option value="cellular_component">Cellular Component</option>
<option value="molecular_function">Molecular Function</option>
</select>
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if I want to simulate http query using lwp method as follows

my $response=$browser->post($url,["ontologies[]" => "ALL"])
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it still doesn't work

thanks for your reply ,but the unquoted select1 select2 will generate syntax error

That's not true! Quoting of identifiers followed by "=>" is optional. See perlop and perldata.

use strict;
use warnings;

use Data::Dumper qw( Dumper );

print Dumper
     [ select1 => 'Component_1_1',
       select1 => 'Component_1_2',
       select2 => 'Component_2_3',
     ];
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>perl 710263.pl
$VAR1 = [
          'select1',
          'Component_1_1',
          'select1',
          'Component_1_2',
          'select2',
          'Component_2_3'
        ];
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Note that ontologies[] is not an identifier, so you will have to quote that.

it still doesn't work

You've misspelled "All". If you still have problems after fixing that one, perhaps the server is expecting other fields you didn't show us or some cookies.

See also perldata, perllol, perlreftut, perldsc, perlref.

I tried that ,but without success.