JavaScript Examples Bible - UserWorks Technologies

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JavaScript Examples Bible: The Essential Companion to JavaScript Bible
Examples Highlights
✦ Listing 28-1 provides numerous functions that examine navigator object
properties. The functions examples are provided more as demonstrations of
specific values your scripts may need to look for, rather than as some super
“browser sniffer.” Determining specific IE versions is a bit tricky, so observe
how to go about it by way of the navigator.appVersion property.
✦ NN4+ provides access to browser preferences via the navigator.
preference() method, as shown in Listing 28-2. To implement this feature in
a production page, you’ll need to use signed scripts.
✦ Experiment with the screen.availLeft and screen.availTop properties in
NN4+, especially in the Windows environment to see how the taskbar affects
these property values.
✦ For IE4+/Windows, follow the sequence of examples for the userProfile
object’s methods to see how scripts can read user profile fields.
clientInformation Object (IE4+)
and navigator Object (All)
Properties
appCodeName
appName
appVersion
userAgent
navigator.appCodeName
NN2 NN3 NN4 NN6 IE3/J1 IE3/J2 IE4 IE5 IE5.5
Compatibility ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓
Example
Listing 28-1 provides a number of reusable functions that your scripts can
employ to determine a variety of information about the currently running browser.
This is not intended in any way to be an all-inclusive browser-sniffing routine;
instead, I offer samples of how to extract information from the key navigator
properties to determine various browser conditions.
All functions in Listing 28-1 return a Boolean value inline with the pseudoquestion
presented in the function’s name. For example, the isWindows() function
returns true if the browser is any type of Windows browser; otherwise, it returns
false. (In Internet Explorer 3, the values are 0 for false and -1 for true, but those