I want to get more drop down boxes to appear upon selection

Hi,

I want my web site to start off by displaying a drop down box. The user has a list of four choices. Based on the choice they select, it will make a list more drop down boxes plus a text box.

I tried searching for ways to do this, but I must be querying the wrong words into Google or something but not many useful things come up.

DropdownBox_Courses

   English

   Math

   Science

   History

 

(English Selected)

Take this class on ...

  Fridays?

  Saturdays?

 

Time preferred ...

Noon?

2:00?

Enter your student ID... [Textbox]

(Math Selected)

Take this class on ...

Wednesdays?

Thursdays?

 

Time preferred ...

1:00?

3:00?

Enter your student ID... [Textbox]

 

... So on and so fourth.

The p ...