Multiple Select Option Set

Hello!

Can anybody help me with this:

I have two (html) Dropdowns(DDL1 & DDL2) in which the values get filled dynamically based on a WebService call.

My requirement is - when i select DDL1, the values in DDL2 should be filled based on DDL1 selected value.Is this possible?

Any suggestions would be a great help!

Thanks,

Manu.