my $selectedName = param('unit_name');

##</code><code>##

 print "<input type='hidden' name='unit_name' value='This gets set via javascript'>";  

##</code><code>##

    print "<td>\n"; # If you want all buttons in a single TD .. otherwise, this could be <tr>
    while (my @data = $sth->fetchrow_array()) 
    {
        $unit_name = $data[0];
        push(@unitNames, $unit_name);
        print "$unit_name<br>";
        print "<input type='image' name='$unit_name' id='$unit_name' alt=airConButton src='../../images/unit.jpg'
          height='100px' width='100px' onclick='this.form.unit_name.value =\"$unit_name\";this.form.submit()'></input>";
    }
   # Close the TD or TR here..