Object programming
Cart
0
1
…
n
Description display(where)
Price
Description display(where)
Price
Description display(where)
Price
…
Properties
Method
top.hidden
jackson.html with the
following buttons:
• Place order
• View order
cart.html with the following
functions:
1.addcart(desc, price)
2.additem(desc, price, itemcnt)
3.viewcart()
4.prtitem(where)
5.delitem(itemcnt)
top.main
Jackson electronic example
Shopping cart logic
1.
2.
3.
4.
5.
6.
cart.html is always accessible in top.hidden frame
jackson.html is displayed in top.main frame
When the [Place Order] button is clicked, the addcart function
is called, passing along the product description and price from
the order
The addcart function will call the additem function to store
the description, price, and current count of the item onto the
shopping cart  an alert message is issued as confirmation
that the additem function is successfully executed 
Steps 3 and 4 will be repeated until the user clicks the [View
Order] button which triggers the viewcart function
The viewcart function will display the content of the cart
object in top.main frame as a table by calling the display
method of the cart object  prtitem function with a delitem
function link
top.hidden
banner.html with image
map: banner.jpg
cart.html with the following
functions:
1.additem(desc, price, itemcnt)
2.delitem(itemcnt)
brkfst.html
3.addcart(desc, price)
lunch.html
4.prtitem(where)
5.viewcart()
dinner.html
top.main
Kelsey’s Diner example
Shopping cart logic
1.
2.
3.
4.
5.
6.
cart.html is always accessible in top.hidden frame
Assume brkfst.html is displayed in top.main frame
user selected an item off the menu by clicking on the Order
link which triggers the addcart function with its description
and price
The addcart function will call the additem function to store
the description, price, and current count of the item onto the
shopping cart  an alert message is issued as confirmation
that the additem function is successfully executed 
Steps 3 and 4 will be repeated until the user clicks the View
Order link which triggers the viewcart function
The viewcart function will display the content of the cart
object in top.main frame as a table by calling the display
method of the cart object  prtitem function with a delitem
function link