Enabling and disabling fields based on multiple values from combo box

[hksahoo]

I have a combo-box with drop-down list to select with check boxes. The options are CASH, CHEQUE, DD, LETTER, PRAYER. One can also select multiple options like CASH and DD, CHEQUE and DD, DD and LETTER etc. I want that if DD is not selected then the DD_NO, DD_DATE, DD_AMT fields should be disabled. Similarly if only CASH is selected, then CHEQUE_NO, CHEQUE_DATE, CHEQUE_AMT and also DD_NO, DD_DATE, DD_AMT fields should be disabled. Pl. advise how to do it.

hksahoo