Please help with form checkbox

please anyone help me
i have registration form of 7 step like

1-step:student info :after press go to next step step-2 page will show like

2-step:parent info
.
.
.
7-step:final step

all are ok but this is so lengthy process.
so i want to show only first step and if user want to input more i want to use 6 checkbox after first form input and before submit button press he can check any or all of the checkbox according to checkbox check registration form will show and data will store to database after all checked form input.
any help will appreciate please.

You can use Javascript to hide the extra content, and when they select a checkbox, those new areas are disappeared.

How to do this i am silly know with javascript.
please give me some idea.
please

Here is the perfect example and the coding for it.

http://www.randomsnippets.com/2008/02/12/how-to-hide-and-show-your-div/