php - autosum in pdf file -

i want auto sum in pdf, example, when tick checkbox, automatically calculate sum of ticked box.

here code:

if($books){ $i=1; foreach($books $b){     if($b->code){         $bodycontent .= '<tr><td>'.$i.'</td><td><input type="checkbox" name="g'.$i.'" value="0" /></td><td><input type="checkbox" name="d'.$i.'" value="0" /></td><td><input type="checkbox" name="u'.$i.'" value="0" /></td><td>'.$u->code.': '.$u->name.'</td></tr>';         $i++;     } } $bodycontent .= '<tr><td></td><td><input type="text" name="g_total" size="3" /></td><td><input type="text" name="d_total" size="3" /></td><td><input type="text" name="u_total" size="3" /></td><td>totals</td></tr>';