JavaScript Examples Bible - UserWorks Technologies

Navigator
and Other
Environment
Objects
(Chapter 28)
Objects covered in this chapter are somewhat distant
from the document and its content, but they are no less
important to scripters. Any script branching that relies on
knowing details about the browser version or other aspects
of the environment running the browser calls upon the
navigator object. Properties of the navigator object (also
named the clientInformation object in IE4+), reveal
browser brand and version information, as well as operating
system and, in some cases, encryption powers of the browser.
Using signed scripts with NN4+, you can even script modification
to browser preferences.
Avoid using navigator object properties for browser
version branching when more sophisticated techniques —
notably object detection as described in Chapter 14 of the
JavaScript Bible — are less dependent upon future quirks in
object model developments. But version detection is perfect
when you know that a special workaround is needed for some
glitch in a specific version or class of browser. For example,
NN4/Windows can exhibit some strange behavior when
attempting to print a page whose content relies on script
execution. Provided you have a code workaround for the
problem, you can divert script execution for just that version
of NN in just the Windows version.
Examples in this chapter also touch upon the screen
object and the IE/Windows userProfile object. The screen
object is useful in determining the size of a new window, but
there is little need to script the userProfile object.
12
C H A P T E R
✦ ✦ ✦ ✦
In This Chapter
Determining the
user’s browser,
operating system,
and video monitor
settings
Modifying NN4+
browser preferences
Retrieving IE4+ user
profile information
✦ ✦ ✦ ✦