Dear Friend
You can Use The following Code :
<script language="javascript">
function selectA() {
var selA = document.test.typeA.value;
var objB = document.test.typeB;
objB.options.length = 0;
if (selA=='A') {
objB.options[0] = new Option('A1','A1');
objB.options[1] = new Option('A2','A2');
objB.options[2] = new Option('A3','A3');
}else if (selA=='B') {
objB.options[0] = new Option('B1','B1');
objB.options[1] = new Option('B2','B2');
objB.options[2] = new Option('B3','B3');
}else if (selA=='C') {
objB.options[0] = new Option('C1','C1');
objB.options[1] = new Option('C2','C2');
objB.options[2] = new Option('C3','C3');
}
}
</script>
test is the name of my form and typeA is the first Combo box and typeB is the second combo box, also you can call this function with one button and one combo box, if you have any question please email me
Regards
Shahroozj@Hotmail.com