you can bind dropdown list dynamically using jquery ajax call to your mvc controller and action.
just make a html feild
<selct id="dd">
and call your ajax code on your first dropdown change event.
$('#firstDD').on('change',funtion(){
var id=$(this).val();
$.ajax({
method:'Post',
url:'@Url.Action("Action","Controller")',
data:id,
datatype:'json',
success:function(res){
var op='';
if(res.length>0){
<pre>$.each(res, function(k, v) {
op +='<option value="'+k.value+'">'+k.text+'</option>';
});
$('#dd').empty();
$('#dd').append(op);
}
}
});
});