Timers

In WML, you can use timers to perform timed actions. A timer measures a time period, and the browser undertakes some action when that period has expired . For example, if I assign a card's ontimer attribute to the ID of another card, the browser will navigate to that card when the timer finishes:

 <?xml version="1.0"?>  <!DOCTYPE wml PUBLIC "-//WAPFORUM//DTD WML 2.0//EN"     "http://www.wapforum.org/dtd/wml20.dtd" > <wml>  <card id="Card1" ontimer="#card2" title="Timers">   .   .   .   </card>  .     .     . 

You create a timer with the <timer> element and give it a time period (measured in tenths of seconds) with the value attribute, like this, where I'm giving this card's timer a period of 10 seconds:

 <?xml version="1.0"?>  <!DOCTYPE wml PUBLIC "-//WAPFORUM//DTD WML 2.0//EN"     "http://www.wapforum.org/dtd/wml20.dtd" > <wml>     <card id="Card1" ontimer="#card2" title="Timers">         <p align="center"><b>Timers</b></p>  <timer value="100"/>  <p>             In ten seconds, you'll be redirected             to the second card.         </p>     </card>     .     .     . 

All that remains is to add the targeted card, card2:

Listing ch20_18.wml

 <?xml version="1.0"?> <!DOCTYPE wml PUBLIC "-//WAPFORUM//DTD WML 2.0//EN"     "http://www.wapforum.org/dtd/wml20.dtd" > <wml>     <card id="Card1" ontimer="#card2" title="Timers">         <p align="center"><b>Timers</b></p>         <timer value="100"/>         <p>             In ten seconds, you'll be redirected             to the second card.         </p>     </card>  <card id="card2" title="Welcome">   <p>   Welcome to card 2.   </p>   </card>  </wml> 

Now when you open this deck, you'll see card 1, as shown in Figure 20-17. After 10 seconds, the browser will navigate to card 2. (Note that, as shown in the figure, Klondike features a timer counter at lower right; here, it's indicating that there are 7 seconds left in the timer.)

Figure 20-17. Using a timer.