[]Checkbox1
[]Checkbox2
[]Checkbox3

This shuld help us display

when check box 1 is clicked,
Input for checkbox1 [    ]

-----------------------
Submit
when checkbox1 and checbox2 is clicked,

Input for checkbox1 [    ]
Input for checkbox2 [    ]

-----------------------
Submit
 and so forth.
##</code><code>##

$cgi->checkbox_group(-name=>'checkoptions',-value=> ['Checkbox1', 'Checkbox2', 'Checkbox3'], -onClick=>"this.form.submit()")
my $flag= $cgi->param('checkoptions');
if($flag eq 'Checkbox1'){  print "Input for checkbox1  ",$cgi->textfield(-name=>"option1");}