What? That makes no sense. You really need to get a better handle at the HTML that is generated by CGI. Both scrolling_list and popup_menu produce and HTML select list. The only difference between the two are scrolling_list allows multiple selects and scrolling_list lets you set the size of the window.

#!/usr/bin/perl

use strict;
use warnings;

use CGI qw/:standard/;

print
    popup_menu( -name => 'color_pm',
     -values => [ 'red', 'green', 'blue', 'chartreuse' ] ),
    "\n\n",
    scrolling_list( -name => 'color_sl',
     -values   => [ 'red', 'green', 'blue', 'chartreuse' ],
     -size     => 3,
     -multiple => 'true' );
[download]

produces:

<select name="color_pm" >
  <option value="red">red</option>
  <option value="green">green</option>
  <option value="blue">blue</option>
  <option value="chartreuse">chartreuse</option>
</select>

<select name="color_sl"  size="3" multiple="multiple">
  <option value="red">red</option>
  <option value="green">green</option>
  <option value="blue">blue</option>
  <option value="chartreuse">chartreuse</option>
</select>
[download]

so if your window *gets huge" pass the appropriate options to reduce its size.