Hide Dropdowns from each other with if statement???

[eluser]Nummero2[/eluser]
Hi,

i´ve got a create form which sents data to a mysql table. In this form I´ve got two dropdown menues.

Is it possible to make one of them invisible if a certain value is selected in the other one?

Example:

Dropdown 1 values: no value, one, two, three;
Dropdown 2 values: no value, 99, 88, 77;

So I want to achieve that when the user selects a value in Dropdown 1 like "one" the Dropdown 2 is hiding automatically or doesn´t allow an entry at least.

With Dropdown 2 vice versa.

Hoping for your great ideas as always :-)

Greetings Sebastian