Another is to convert them to a select drop down. We are not building
WML capability in POTR yet.
WALL is still useful for us as it can support cHTML devices and will automatically
take care of XHTML implementation variations in different browsers. It can even
generate some cool menus for us! Take a look at the following screenshot.
Device Detection and Capabilities
We looked at what WALL can do and how easy it is to implement it. But how
does it do that? WALL, and many other open-source (and commercial) tools use
WURFL??”Wireless Universal Resource File. The mDevInf tool that we saw earlier
in this chapter is entirely based on WURFL. WURFL is a massive XML file, listing
capabilities of all known mobile devices (almost!). It is actively maintained
and also derives information from UAProf??”another standard for managing
device capabilities.
Chapter 4
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At the heart of any device detection is the User Agent header sent by the browser. All
device detection techniques check the User Agent ($_SERVER['HTTP_USER_AGENT']
variable for PHP) and look up their database to find the characteristics of that device.
Here are some of the things WURFL can tell you about a device:
Screen size of the device
Supported image, audio, video, ringtone, wallpaper, and screensaver formats
Whether the device supports Unicode
Is it a wireless device? What markup does it support?
What XHTML MP/WML/cHTML features does it support? Does it work
with tables? Can it work with standard HTML?
Does it have a pointing device? Can it use CSS?
Does it have Flash Lite/J2ME support? What features?
Can images be used as links on this device? Can it display image and text on
the same line?
If this is an iMode phone, what region is it from? Japan? US? Europe?
Does the device auto-expand a select drop down? Does it have inline input
for text fields?
What SMS/MMS features are supported?
The list goes on.
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