How to deselect the selectBox

[mamidira]

I had 3 select boxes in my form where all the 3 are dependent on the above select box.
i.e., the values in the second select box is dependent on the selection of the first selectbox and same with the third selectBox.

I am able to do this thing..

My problem is if i change the value in first select box then the other two selectboxex should become null or default values..

please help in this issue......

[acoder]

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