使用javascript隐藏和显示下拉列表

I am in a very confused state how to write this code. Actually my requirement is .. I have a 5 drop down boxes in which first one should be constant and others should remain hidden. Based on the option selected in the first drop down box i need to display other drop downs. But here comes the tricky part... If for example.. i have selected "java" option in main drop down box java drop down box should appear , if again i select another option along with java box another drop down box should also appear. I am in a very confused state how to write this