Page 95 - DCAP512_WAP_AND_WML

Unit 6: Card Navigation

found and are trying to recover back onto the same drive.” More tips are sprinkled all Notes
through the book, such as: “Do not power up a device that has obvious physical damage.
Activate the write-protect switch or tab on any problem removable media such as tape
cartridges and floppies; many good backups are overwritten during a crisis.”
There are also dos: “When facing data loss, stop and review the situation. The process of
reviewing and writing down a synopsis of the situation has the dual purpose of preparing
for a recovery and inducing a calm.” Also, “Do no harm.” A lesson from the medical
profession.
Contrary to popular belief, CD audio is “remarkably resilient to data loss,” informs the
author. “Bits of dust or dirt on the surface of the disk, or even small scratches, will often
not impede the performance of the CD player or the CD-ROM.”
One of the techniques that makes this possible is ECC (error-correcting code), “a special
data encoding protocol that uses a combination of redundant information and special data
positioning, to make it possible to detect and recover from missing bits of data.”

6.7 Summary

 Apart from the common attributes xml:lang, id and class, the <a> element supports
attributes called href, title and access key. href is used to specify the destination of a
hyperlink.
 The destination may be within a deck, or a card in another deck that is also on the same site
or the card may be in a deck which is on another site.

 Anchor links enable the navigation between different WML cards.
 If you select an anchor link, you will be brought to another WML card in the current deck
or in another deck.

 The <do> element is used to associate a task to a certain user interface element of a
wireless device.

 The task will be done if the user activates the user interface element.
 The mapping between a <do> element and a user interface element depends on the actual
wireless device.

 Navigation instructions shift from the current card to the next active card. Navigation can
happen between cards in the same deck, moving from deck to deck, between applications
and between sites.
 The core elements of a WML Deck are wml, head, card and template.
 A hot spot is a “clickable” area on screen that directs navigation or other actions. Link code
connects a hot spot to a task. Hot spot links are defined with anchor tags, either <a> or
<anchor>. We can use hotspots to connect users to any file on the web. We can utilize to
point users to other decks and applications. Hotspots are mainly used to navigate users
from one card to another.

6.8 Keywords

CDMA: Code Division Multiple Access
CDPD: Cellular Digital Packet Data CDPD

CSD: Circuit-Switched Data

LOVELY PROFESSIONAL UNIVERSITY 89