As davido has suggested , go through the CGI docs
a quick answer to your question ,you can use something like this 
use CGI;
my $cgi;
my @selected_values;
$cgi = new CGI;
@selected_values = $cgi->param('users_list');

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In reply to Re: how to get multiple options selected in webpage by mkirank
in thread how to get multiple options selected in webpage by kamesh3183

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