Currently, Web pages are typically defined using HyperText Markup Language ("HTML").
解答例
HTML provides a standard set of tags that define how a Web page is to be displayed.
When a user indicates to the browser to display a Web page, the browser sends a request to the server computer system to transfer to the client computer system an HTML document that defines the Web page.
When the requested HTML document is received by the client computer system, the browser displays the Web page as defined by the HTML document.
The HTML document contains various tags that control the displaying of text, graphics, controls, and other features.
The HTML document may contain URLs of other Web pages available on that server computer system or other server computer systems.
The World Wide Web is especially conducive to conducting electronic commerce.
Many Web servers have been developed through which vendors can advertise and sell product.
The products can include items (e.g., music) that are delivered electronically to the purchaser over the Internet and items (e.g., books) that are delivered through conventional distribution channels (e.g., a common carrier).
A server computer system may provide an electronic version of a catalog that lists the items that are available.
A user, who is a potential purchaser, may browse through the catalog using a browser and select various items that are to be purchased.
When the user has completed selecting the items to be purchased, the server computer system then prompts the user for information to complete the ordering of the items.
This purchaser-specific order information may include the purchaser's name, the purchaser's credit card number, and a shipping address for the order.
The server computer system then typically confirms the order by sending a confirming Web page to the client computer system and schedules shipment of the items.
Since the purchaser-specific order information contains sensitive information (e.g., a credit card number), both vendors and purchasers want to ensure the security of such information.
Security is a concern because information transmitted over the Internet may pass through various intermediate computer systems on its way to its final destination.
The information could be intercepted by an unscrupulous person at an intermediate system.
To help ensure the security of the sensitive information, various encryption techniques are used when transmitting such information between a client computer system and a server computer system.
Even though such encrypted information can be intercepted, because the information is encrypted, it is generally useless to the interceptor.
Nevertheless, there is always a possibility that such sensitive information may be successfully decrypted by the interceptor.
Therefore, it would be desirable to minimize the sensitive information transmitted when placing an order.
The selection of the various items from the electronic catalogs is generally based on the "shopping cart" model.
When the purchaser selects an item from the electronic catalog, the server computer system metaphorically adds that item to a shopping cart.
When the purchaser is done selecting items, then all the items in the shopping cart are "checked out" (i.e., ordered) when the purchaser provides billing and shipment information.
In some models, when a purchaser selects any one item, then that item is "checked out" by automatically prompting the user for the billing and shipment information.
Although the shopping cart model is very flexible and intuitive, it has a downside in that it requires many interactions by the purchaser.
For example, the purchaser selects the various items from the electronic catalog, and then indicates that the selection is complete.
The purchaser is then presented with an order Web page that prompts the purchaser for the purchaser-specific order information to complete the order.
That Web page may be prefilled with information that was provided by the purchaser when placing another order.
The information is then validated by the server computer system, and the order is completed.
